feat: multiple UI improvements, font settings, and memory file display names (#175)

## Summary

- **fix**: `show_thinking_blocks` setting now persists across sessions — it was defined on the TypeScript side but missing from the Rust `HikariConfig` struct, so serde silently dropped it on every save/load
- **feat**: Tool calls are now rendered as collapsible blocks matching the Extended Thinking block aesthetic, replacing the old inline dropdown approach
- **feat**: Add configurable max output tokens setting
- **feat**: Use random creative names for conversation tabs
- **test**: Significantly expanded frontend unit test coverage
- **docs**: Require tests for all changes in CLAUDE.md
- **feat**: Allow users to specify a custom terminal font (Closes #176)
- **feat**: Display friendly names for memory files derived from the first heading (Closes #177)
- **feat**: Add custom UI font support for the app chrome (buttons, labels, tabs)
- **fix**: Apply custom UI font to the full app interface — `.app-container` was hardcoded, blocking inheritance from `body`; also renamed "Custom Font" to "Custom Terminal Font" for clarity

✨ This PR was created with help from Hikari~ 🌸

Reviewed-on: #175
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src/lib/stores/achievements.test.ts

@@ -0,0 +1,185 @@
+import { describe, it, expect, vi } from "vitest";
+import { get } from "svelte/store";
+import { setMockInvokeResult, emitMockEvent } from "../../../vitest.setup";
+import {
+  achievementsStore,
+  unlockedAchievements,
+  lockedAchievements,
+  achievementsByRarity,
+  achievementProgress,
+  initAchievementsListener,
+} from "./achievements";
+import type { AchievementUnlockedEvent } from "$lib/types/achievements";
+import { playAchievementSound } from "$lib/sounds/achievement";
+
+vi.mock("$lib/sounds/achievement", () => ({
+  playAchievementSound: vi.fn(),
+}));
+
+// Helper to build a minimal unlock event
+function makeEvent(id: AchievementUnlockedEvent["achievement"]["id"]): AchievementUnlockedEvent {
+  return {
+    achievement: {
+      id,
+      name: "Test",
+      description: "Test achievement",
+      icon: "🏆",
+      unlocked_at: null,
+    },
+  };
+}
+
+describe("achievementsStore initial state", () => {
+  it("all achievements start as locked", () => {
+    const state = get(achievementsStore);
+    expect(state.achievements["FirstSteps"].unlocked).toBe(false);
+    expect(state.achievements["GrowingStrong"].unlocked).toBe(false);
+  });
+
+  it("totalUnlocked starts at 0", () => {
+    expect(get(achievementsStore).totalUnlocked).toBe(0);
+  });
+
+  it("lastUnlocked starts as null", () => {
+    expect(get(achievementsStore).lastUnlocked).toBeNull();
+  });
+});
+
+describe("derived stores initial state", () => {
+  it("unlockedAchievements is initially empty", () => {
+    expect(get(unlockedAchievements)).toEqual([]);
+  });
+
+  it("lockedAchievements contains all achievements initially", () => {
+    const locked = get(lockedAchievements);
+    const total = Object.keys(get(achievementsStore).achievements).length;
+    expect(locked.length).toBe(total);
+  });
+
+  it("achievementsByRarity groups achievements into rarity buckets", () => {
+    const byRarity = get(achievementsByRarity);
+    expect(byRarity.common).toBeInstanceOf(Array);
+    expect(byRarity.rare).toBeInstanceOf(Array);
+    expect(byRarity.epic).toBeInstanceOf(Array);
+    expect(byRarity.legendary).toBeInstanceOf(Array);
+    expect(byRarity.common.length).toBeGreaterThan(0);
+  });
+
+  it("achievementProgress shows zero unlocked initially", () => {
+    const progress = get(achievementProgress);
+    expect(progress.unlocked).toBe(0);
+    expect(progress.total).toBeGreaterThan(0);
+    expect(progress.percentage).toBe(0);
+  });
+});
+
+describe("achievementsStore.unlockAchievement", () => {
+  it("marks the achievement as unlocked and updates totalUnlocked", () => {
+    achievementsStore.unlockAchievement(makeEvent("GrowingStrong"));
+    const state = get(achievementsStore);
+    expect(state.achievements["GrowingStrong"].unlocked).toBe(true);
+    expect(state.totalUnlocked).toBe(1);
+    expect(state.lastUnlocked?.id).toBe("GrowingStrong");
+  });
+
+  it("sets unlockedAt from the event's unlocked_at timestamp", () => {
+    achievementsStore.unlockAchievement({
+      achievement: {
+        id: "BlossomingCoder",
+        name: "Blossoming Coder",
+        description: "100k tokens",
+        icon: "🌸",
+        unlocked_at: "2026-01-15T12:00:00.000Z",
+      },
+    });
+    const state = get(achievementsStore);
+    expect(state.achievements["BlossomingCoder"].unlockedAt).toBeInstanceOf(Date);
+  });
+
+  it("does nothing when the achievement is already unlocked", () => {
+    achievementsStore.unlockAchievement(makeEvent("TokenMaster"));
+    const firstTotal = get(achievementsStore).totalUnlocked;
+    achievementsStore.unlockAchievement(makeEvent("TokenMaster"));
+    expect(get(achievementsStore).totalUnlocked).toBe(firstTotal);
+  });
+
+  it("calls playAchievementSound when playSound is true (default)", () => {
+    achievementsStore.unlockAchievement(makeEvent("TokenBillionaire"));
+    expect(playAchievementSound).toHaveBeenCalled();
+  });
+
+  it("does not call playAchievementSound when playSound is false", () => {
+    achievementsStore.unlockAchievement(makeEvent("TokenTreasure"), false);
+    expect(playAchievementSound).not.toHaveBeenCalled();
+  });
+
+  it("logs an error when playAchievementSound throws", () => {
+    vi.mocked(playAchievementSound).mockImplementationOnce(() => {
+      throw new Error("Sound failed");
+    });
+    const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    achievementsStore.unlockAchievement(makeEvent("HelloWorld"));
+    expect(consoleSpy).toHaveBeenCalledWith("Failed to play achievement sound:", expect.any(Error));
+    consoleSpy.mockRestore();
+  });
+});
+
+describe("derived stores after unlocks", () => {
+  it("unlockedAchievements includes previously unlocked achievements", () => {
+    const unlocked = get(unlockedAchievements);
+    expect(unlocked.some((a) => a.id === "GrowingStrong")).toBe(true);
+  });
+
+  it("lockedAchievements excludes previously unlocked achievements", () => {
+    const locked = get(lockedAchievements);
+    expect(locked.some((a) => a.id === "GrowingStrong")).toBe(false);
+  });
+
+  it("achievementProgress reflects the current unlocked count", () => {
+    const progress = get(achievementProgress);
+    expect(progress.unlocked).toBeGreaterThan(0);
+    expect(progress.percentage).toBeGreaterThan(0);
+  });
+});
+
+describe("achievementsStore.updateProgress", () => {
+  it("updates the progress value for an achievement", () => {
+    achievementsStore.updateProgress("FirstMessage", 50);
+    expect(get(achievementsStore).achievements["FirstMessage"].progress).toBe(50);
+  });
+});
+
+describe("achievementsStore.reset", () => {
+  it("resets totalUnlocked to 0 and lastUnlocked to null", () => {
+    achievementsStore.reset();
+    const state = get(achievementsStore);
+    expect(state.totalUnlocked).toBe(0);
+    expect(state.lastUnlocked).toBeNull();
+  });
+});
+
+describe("initAchievementsListener", () => {
+  it("unlocks an achievement when the achievement:unlocked event fires", async () => {
+    await initAchievementsListener();
+    emitMockEvent("achievement:unlocked", makeEvent("FirstSteps"));
+    expect(get(achievementsStore).achievements["FirstSteps"].unlocked).toBe(true);
+  });
+
+  it("loads saved achievements from the backend without playing sounds", async () => {
+    setMockInvokeResult("load_saved_achievements", [makeEvent("ConversationStarter")]);
+    await initAchievementsListener();
+    expect(get(achievementsStore).achievements["ConversationStarter"].unlocked).toBe(true);
+    expect(playAchievementSound).not.toHaveBeenCalled();
+  });
+
+  it("logs an error when loading saved achievements fails", async () => {
+    setMockInvokeResult("load_saved_achievements", new Error("Storage unavailable"));
+    const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    await initAchievementsListener();
+    expect(consoleSpy).toHaveBeenCalledWith(
+      "Failed to load saved achievements:",
+      expect.any(Error)
+    );
+    consoleSpy.mockRestore();
+  });
+});

src/lib/stores/character.test.ts

@@ -0,0 +1,124 @@
+import { describe, it, expect, beforeEach, vi, afterEach } from "vitest";
+import { get } from "svelte/store";
+import { characterState, characterInfo } from "./character";
+
+describe("characterState store", () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+    characterState.reset();
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  describe("initial state", () => {
+    it("starts in idle state", () => {
+      expect(get(characterState)).toBe("idle");
+    });
+  });
+
+  describe("setState", () => {
+    it("sets the character state", () => {
+      characterState.setState("thinking");
+      expect(get(characterState)).toBe("thinking");
+    });
+
+    it("can set any valid state", () => {
+      const states = [
+        "idle",
+        "thinking",
+        "typing",
+        "coding",
+        "searching",
+        "mcp",
+        "permission",
+        "success",
+        "error",
+      ] as const;
+      for (const state of states) {
+        characterState.setState(state);
+        expect(get(characterState)).toBe(state);
+      }
+    });
+
+    it("cancels any active temporary state timer", () => {
+      characterState.setTemporaryState("success", 5000);
+      characterState.setState("thinking");
+
+      // Advance past the temporary state duration — should stay as thinking
+      vi.advanceTimersByTime(6000);
+      expect(get(characterState)).toBe("thinking");
+    });
+  });
+
+  describe("setTemporaryState", () => {
+    it("sets the character state immediately", () => {
+      characterState.setTemporaryState("success", 2000);
+      expect(get(characterState)).toBe("success");
+    });
+
+    it("reverts to idle after the specified duration", () => {
+      characterState.setTemporaryState("success", 2000);
+      vi.advanceTimersByTime(2000);
+      expect(get(characterState)).toBe("idle");
+    });
+
+    it("uses 2000ms as the default duration", () => {
+      characterState.setTemporaryState("error");
+      vi.advanceTimersByTime(1999);
+      expect(get(characterState)).toBe("error");
+      vi.advanceTimersByTime(1);
+      expect(get(characterState)).toBe("idle");
+    });
+
+    it("cancels a previous temporary state timer when a new one is set", () => {
+      characterState.setTemporaryState("success", 5000);
+      characterState.setTemporaryState("error", 1000);
+
+      // First timer would have fired at 5000ms but was cancelled
+      vi.advanceTimersByTime(1000);
+      expect(get(characterState)).toBe("idle");
+    });
+  });
+
+  describe("reset", () => {
+    it("resets the state to idle", () => {
+      characterState.setState("thinking");
+      characterState.reset();
+      expect(get(characterState)).toBe("idle");
+    });
+
+    it("cancels any pending temporary state timer", () => {
+      characterState.setTemporaryState("success", 5000);
+      characterState.reset();
+
+      // Should now be idle and should NOT revert again after timer fires
+      expect(get(characterState)).toBe("idle");
+      vi.advanceTimersByTime(5000);
+      expect(get(characterState)).toBe("idle");
+    });
+  });
+});
+
+describe("characterInfo derived store", () => {
+  beforeEach(() => {
+    characterState.reset();
+  });
+
+  it("returns the info object for the current state", () => {
+    const info = get(characterInfo);
+    expect(info).toBeDefined();
+    expect(typeof info.label).toBe("string");
+  });
+
+  it("updates when the character state changes", () => {
+    characterState.setState("thinking");
+    const thinkingInfo = get(characterInfo);
+
+    characterState.setState("idle");
+    const idleInfo = get(characterInfo);
+
+    expect(thinkingInfo.label).not.toBe(idleInfo.label);
+  });
+});

src/lib/stores/claude.test.ts

@@ -0,0 +1,139 @@
+import { describe, it, expect, afterEach } from "vitest";
+import { get } from "svelte/store";
+import {
+  claudeStore,
+  hasPermissionPending,
+  hasQuestionPending,
+  isClaudeProcessing,
+} from "./claude";
+import { conversationsStore } from "./conversations";
+import { characterState } from "$lib/stores/character";
+import type { PermissionRequest, UserQuestionEvent } from "$lib/types/messages";
+
+describe("claudeStore (compatibility wrapper)", () => {
+  afterEach(() => {
+    conversationsStore.revokeAllTools();
+    conversationsStore.clearPermission();
+    conversationsStore.clearQuestion();
+    conversationsStore.setConnectionStatus("disconnected");
+    characterState.setState("idle");
+  });
+
+  describe("getGrantedTools", () => {
+    it("returns an empty array when no tools are granted", () => {
+      expect(claudeStore.getGrantedTools()).toEqual([]);
+    });
+
+    it("returns granted tools as an array", () => {
+      conversationsStore.grantTool("Read");
+      conversationsStore.grantTool("Write");
+
+      const tools = claudeStore.getGrantedTools();
+
+      expect(tools).toContain("Read");
+      expect(tools).toContain("Write");
+    });
+  });
+
+  describe("reset", () => {
+    it("clears terminal lines and resets processing state", () => {
+      conversationsStore.setProcessing(true);
+      conversationsStore.grantTool("Edit");
+
+      claudeStore.reset();
+
+      expect(get(conversationsStore.isProcessing)).toBe(false);
+      expect(claudeStore.getGrantedTools()).toEqual([]);
+    });
+  });
+});
+
+describe("hasPermissionPending derived store", () => {
+  afterEach(() => {
+    conversationsStore.clearPermission();
+  });
+
+  it("is false when there are no pending permissions", () => {
+    expect(get(hasPermissionPending)).toBe(false);
+  });
+
+  it("is true when there is a pending permission request", () => {
+    const request: PermissionRequest = {
+      id: "perm-1",
+      tool: "Bash",
+      description: "Run a shell command",
+      input: { command: "ls" },
+    };
+
+    conversationsStore.requestPermission(request);
+
+    expect(get(hasPermissionPending)).toBe(true);
+
+    conversationsStore.clearPermission();
+  });
+});
+
+describe("hasQuestionPending derived store", () => {
+  afterEach(() => {
+    conversationsStore.clearQuestion();
+  });
+
+  it("is false when there is no pending question", () => {
+    expect(get(hasQuestionPending)).toBe(false);
+  });
+
+  it("is true when there is a pending question", () => {
+    const question: UserQuestionEvent = {
+      id: "q-1",
+      question: "Which approach do you prefer?",
+      options: [{ label: "A" }, { label: "B" }],
+      multi_select: false,
+    };
+
+    conversationsStore.requestQuestion(question);
+
+    expect(get(hasQuestionPending)).toBe(true);
+  });
+});
+
+describe("isClaudeProcessing derived store", () => {
+  afterEach(() => {
+    conversationsStore.setConnectionStatus("disconnected");
+    characterState.setState("idle");
+  });
+
+  it("is false when disconnected regardless of character state", () => {
+    conversationsStore.setConnectionStatus("disconnected");
+    characterState.setState("thinking");
+
+    expect(get(isClaudeProcessing)).toBe(false);
+  });
+
+  it("is false when connected but in idle state", () => {
+    conversationsStore.setConnectionStatus("connected");
+    characterState.setState("idle");
+
+    expect(get(isClaudeProcessing)).toBe(false);
+  });
+
+  it("is true when connected and in thinking state", () => {
+    conversationsStore.setConnectionStatus("connected");
+    characterState.setState("thinking");
+
+    expect(get(isClaudeProcessing)).toBe(true);
+  });
+
+  it("is true when connected and in coding state", () => {
+    conversationsStore.setConnectionStatus("connected");
+    characterState.setState("coding");
+
+    expect(get(isClaudeProcessing)).toBe(true);
+  });
+
+  it("is true when connected and in searching state", () => {
+    conversationsStore.setConnectionStatus("connected");
+    characterState.setState("searching");
+
+    expect(get(isClaudeProcessing)).toBe(true);
+  });
+});

src/lib/stores/clipboard.test.ts

@@ -0,0 +1,675 @@
+/**
+ * Clipboard Store Tests
+ *
+ * Tests the pure helper functions and store actions from the clipboard store:
+ * - detectLanguage: identifies programming language from code content
+ * - formatTimestamp: converts an ISO timestamp to a relative time string
+ * - Store actions: loadEntries, captureClipboard, deleteEntry, togglePin, etc.
+ * - Derived stores: filteredEntries (language + search filtering), languages
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { get } from "svelte/store";
+import { clipboardStore } from "$lib/stores/clipboard";
+import { setMockInvokeResult } from "../../../vitest.setup";
+
+describe("detectLanguage", () => {
+  describe("TypeScript detection", () => {
+    it("detects import statements", () => {
+      expect(clipboardStore.detectLanguage("import React from 'react';")).toBe("typescript");
+    });
+
+    it("detects export statements", () => {
+      expect(clipboardStore.detectLanguage("export function foo() {}")).toBe("typescript");
+    });
+
+    it("detects const declarations", () => {
+      expect(clipboardStore.detectLanguage("const x = 1;")).toBe("typescript");
+    });
+
+    it("detects interface declarations", () => {
+      expect(clipboardStore.detectLanguage("interface Foo {\n  bar: string;\n}")).toBe(
+        "typescript"
+      );
+    });
+
+    it("detects type aliases", () => {
+      expect(clipboardStore.detectLanguage("type MyType = string | number;")).toBe("typescript");
+    });
+  });
+
+  describe("Python detection", () => {
+    it("detects def statements", () => {
+      expect(clipboardStore.detectLanguage("def foo():\n  pass")).toBe("python");
+    });
+
+    it("detects async def statements", () => {
+      expect(clipboardStore.detectLanguage("async def bar():\n  pass")).toBe("python");
+    });
+
+    it("detects from imports", () => {
+      expect(clipboardStore.detectLanguage("from os import path")).toBe("python");
+    });
+
+    it("detects the __name__ guard", () => {
+      expect(clipboardStore.detectLanguage("if __name__ == '__main__':\n  main()")).toBe("python");
+    });
+  });
+
+  describe("Rust detection", () => {
+    it("detects fn declarations", () => {
+      expect(clipboardStore.detectLanguage('fn main() {\n  println!("hello");\n}')).toBe("rust");
+    });
+
+    it("detects impl blocks", () => {
+      expect(clipboardStore.detectLanguage("impl Foo {\n  pub fn new() -> Self {}\n}")).toBe(
+        "rust"
+      );
+    });
+
+    it("detects struct declarations", () => {
+      expect(clipboardStore.detectLanguage("struct Point {\n  x: f64,\n  y: f64,\n}")).toBe("rust");
+    });
+
+    it("detects enum declarations", () => {
+      expect(clipboardStore.detectLanguage("enum Direction {\n  North,\n  South,\n}")).toBe("rust");
+    });
+
+    it("detects mod declarations", () => {
+      expect(clipboardStore.detectLanguage("mod utils;")).toBe("rust");
+    });
+
+    it("detects pub visibility", () => {
+      expect(clipboardStore.detectLanguage("pub fn exported() {}")).toBe("rust");
+    });
+  });
+
+  describe("Go detection", () => {
+    it("detects package declarations", () => {
+      expect(clipboardStore.detectLanguage("package main")).toBe("go");
+    });
+
+    it("detects func declarations", () => {
+      expect(clipboardStore.detectLanguage("func main() {}")).toBe("go");
+    });
+  });
+
+  describe("PHP detection", () => {
+    it("detects the PHP open tag", () => {
+      expect(clipboardStore.detectLanguage("<?php\necho 'hello';")).toBe("php");
+    });
+  });
+
+  describe("SQL detection", () => {
+    it("detects SELECT statements", () => {
+      expect(clipboardStore.detectLanguage("SELECT * FROM users WHERE id = 1")).toBe("sql");
+    });
+
+    it("detects INSERT statements", () => {
+      expect(clipboardStore.detectLanguage("INSERT INTO users (name) VALUES ('Alice')")).toBe(
+        "sql"
+      );
+    });
+
+    it("detects CREATE statements", () => {
+      expect(clipboardStore.detectLanguage("CREATE TABLE users (id INT PRIMARY KEY)")).toBe("sql");
+    });
+
+    it("detects SQL case-insensitively", () => {
+      expect(clipboardStore.detectLanguage("select * from users")).toBe("sql");
+    });
+  });
+
+  describe("HTML detection", () => {
+    it("detects DOCTYPE declarations", () => {
+      expect(clipboardStore.detectLanguage("<!DOCTYPE html>")).toBe("html");
+    });
+
+    it("detects html tags", () => {
+      expect(clipboardStore.detectLanguage("<html><body></body></html>")).toBe("html");
+    });
+
+    it("detects div tags", () => {
+      expect(clipboardStore.detectLanguage("<div class='foo'>bar</div>")).toBe("html");
+    });
+
+    it("detects span tags", () => {
+      expect(clipboardStore.detectLanguage("<span>text</span>")).toBe("html");
+    });
+  });
+
+  describe("JSON detection", () => {
+    it("detects JSON object syntax", () => {
+      expect(clipboardStore.detectLanguage('{"name": "test", "value": 42}')).toBe("json");
+    });
+
+    it("detects JSON with hyphenated keys", () => {
+      expect(clipboardStore.detectLanguage('{"my-key": "value"}')).toBe("json");
+    });
+  });
+
+  describe("YAML detection", () => {
+    it("detects YAML document separator", () => {
+      expect(clipboardStore.detectLanguage("---\nkey: value\nother: 123")).toBe("yaml");
+    });
+  });
+
+  describe("C detection", () => {
+    it("detects #include directives", () => {
+      expect(clipboardStore.detectLanguage("#include <stdio.h>\nint main() {}")).toBe("c");
+    });
+
+    it("detects #define directives", () => {
+      expect(clipboardStore.detectLanguage("#define MAX 100")).toBe("c");
+    });
+
+    it("detects #ifdef directives", () => {
+      expect(clipboardStore.detectLanguage("#ifdef DEBUG\n// debug code\n#endif")).toBe("c");
+    });
+  });
+
+  describe("Java detection", () => {
+    it("detects public class declarations", () => {
+      expect(clipboardStore.detectLanguage("public class Foo {\n  // ...\n}")).toBe("java");
+    });
+
+    it("detects private static methods", () => {
+      expect(clipboardStore.detectLanguage("private static void helper() {}")).toBe("java");
+    });
+
+    it("detects protected interface declarations", () => {
+      expect(clipboardStore.detectLanguage("protected interface Bar {}")).toBe("java");
+    });
+  });
+
+  describe("Bash detection", () => {
+    it("detects shell variable assignments", () => {
+      expect(clipboardStore.detectLanguage("$HOME=/usr/local")).toBe("bash");
+    });
+
+    it("detects variable assignments with underscores", () => {
+      expect(clipboardStore.detectLanguage("$MY_VAR=some_value")).toBe("bash");
+    });
+  });
+
+  describe("unknown content", () => {
+    it("returns null for plain text", () => {
+      expect(clipboardStore.detectLanguage("Hello, world!")).toBeNull();
+    });
+
+    it("returns null for empty string", () => {
+      expect(clipboardStore.detectLanguage("")).toBeNull();
+    });
+
+    it("returns null for mathematical expressions", () => {
+      expect(clipboardStore.detectLanguage("1 + 1 = 2")).toBeNull();
+    });
+
+    it("returns null for a markdown heading", () => {
+      expect(clipboardStore.detectLanguage("# My Heading\nSome text")).toBeNull();
+    });
+  });
+});
+
+describe("formatTimestamp", () => {
+  const NOW = new Date("2026-03-03T12:00:00.000Z");
+
+  beforeEach(() => {
+    vi.useFakeTimers();
+    vi.setSystemTime(NOW);
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  describe("'Just now' threshold (< 1 minute)", () => {
+    it("returns 'Just now' for a timestamp 30 seconds ago", () => {
+      const ts = new Date("2026-03-03T11:59:30.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("Just now");
+    });
+
+    it("returns 'Just now' for the current moment", () => {
+      const ts = NOW.toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("Just now");
+    });
+
+    it("returns 'Just now' for a timestamp 59 seconds ago", () => {
+      const ts = new Date("2026-03-03T11:59:01.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("Just now");
+    });
+  });
+
+  describe("'Xm ago' threshold (1–59 minutes)", () => {
+    it("returns '1m ago' at exactly 1 minute", () => {
+      const ts = new Date("2026-03-03T11:59:00.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("1m ago");
+    });
+
+    it("returns '5m ago' for a timestamp 5 minutes ago", () => {
+      const ts = new Date("2026-03-03T11:55:00.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("5m ago");
+    });
+
+    it("returns '59m ago' just before the 1-hour threshold", () => {
+      const ts = new Date("2026-03-03T11:01:00.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("59m ago");
+    });
+  });
+
+  describe("'Xh ago' threshold (1–23 hours)", () => {
+    it("returns '1h ago' at exactly 1 hour", () => {
+      const ts = new Date("2026-03-03T11:00:00.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("1h ago");
+    });
+
+    it("returns '2h ago' for a timestamp 2 hours ago", () => {
+      const ts = new Date("2026-03-03T10:00:00.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("2h ago");
+    });
+
+    it("returns '23h ago' just before the 1-day threshold", () => {
+      const ts = new Date("2026-03-02T13:00:00.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("23h ago");
+    });
+  });
+
+  describe("'Xd ago' threshold (1–6 days)", () => {
+    it("returns '1d ago' at exactly 1 day", () => {
+      const ts = new Date("2026-03-02T12:00:00.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("1d ago");
+    });
+
+    it("returns '3d ago' for a timestamp 3 days ago", () => {
+      const ts = new Date("2026-02-28T12:00:00.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("3d ago");
+    });
+
+    it("returns '6d ago' just before the 7-day threshold", () => {
+      const ts = new Date("2026-02-25T12:00:00.000Z").toISOString();
+      expect(clipboardStore.formatTimestamp(ts)).toBe("6d ago");
+    });
+  });
+
+  describe("locale date string (7+ days ago)", () => {
+    it("returns a locale date string for a 2-week-old timestamp", () => {
+      const ts = new Date("2026-02-17T12:00:00.000Z").toISOString();
+      const result = clipboardStore.formatTimestamp(ts);
+      // Should not be a relative time string
+      expect(result).not.toContain("m ago");
+      expect(result).not.toContain("h ago");
+      expect(result).not.toContain("d ago");
+      expect(result).not.toBe("Just now");
+    });
+
+    it("returns a locale date string for a 1-month-old timestamp", () => {
+      const ts = new Date("2026-02-03T12:00:00.000Z").toISOString();
+      const result = clipboardStore.formatTimestamp(ts);
+      expect(result).not.toContain("ago");
+    });
+  });
+});
+
+describe("clipboardStore - derived stores", () => {
+  const makeEntry = (overrides: Record<string, unknown> = {}) => ({
+    id: "entry-1",
+    content: "const x = 1;",
+    language: "typescript",
+    source: "test.ts",
+    timestamp: "2026-03-03T12:00:00.000Z",
+    is_pinned: false,
+    ...overrides,
+  });
+
+  beforeEach(() => {
+    clipboardStore.entries.set([]);
+    clipboardStore.searchQuery.set("");
+    clipboardStore.languageFilter.set(null);
+  });
+
+  describe("filteredEntries - language filter", () => {
+    it("returns all entries when no language filter is set", () => {
+      clipboardStore.entries.set([
+        makeEntry({ id: "1", language: "typescript" }),
+        makeEntry({ id: "2", language: "python" }),
+      ]);
+      const filtered = get(clipboardStore.filteredEntries);
+      expect(filtered).toHaveLength(2);
+    });
+
+    it("filters entries by language", () => {
+      clipboardStore.entries.set([
+        makeEntry({ id: "1", language: "typescript" }),
+        makeEntry({ id: "2", language: "python" }),
+        makeEntry({ id: "3", language: "typescript" }),
+      ]);
+      clipboardStore.languageFilter.set("typescript");
+      const filtered = get(clipboardStore.filteredEntries);
+      expect(filtered).toHaveLength(2);
+      expect(filtered.every((e) => e.language === "typescript")).toBe(true);
+    });
+
+    it("returns empty array when filter matches nothing", () => {
+      clipboardStore.entries.set([makeEntry({ language: "typescript" })]);
+      clipboardStore.languageFilter.set("rust");
+      const filtered = get(clipboardStore.filteredEntries);
+      expect(filtered).toHaveLength(0);
+    });
+  });
+
+  describe("filteredEntries - search query", () => {
+    it("filters by content (case-insensitive)", () => {
+      clipboardStore.entries.set([
+        makeEntry({ id: "1", content: "const HELLO = 1;" }),
+        makeEntry({ id: "2", content: "let world = 2;" }),
+      ]);
+      clipboardStore.searchQuery.set("hello");
+      const filtered = get(clipboardStore.filteredEntries);
+      expect(filtered).toHaveLength(1);
+      expect(filtered[0].id).toBe("1");
+    });
+
+    it("filters by language field", () => {
+      clipboardStore.entries.set([
+        makeEntry({ id: "1", language: "typescript", content: "unrelated" }),
+        makeEntry({ id: "2", language: "python", content: "also unrelated" }),
+      ]);
+      clipboardStore.searchQuery.set("python");
+      const filtered = get(clipboardStore.filteredEntries);
+      expect(filtered).toHaveLength(1);
+      expect(filtered[0].id).toBe("2");
+    });
+
+    it("filters by source field", () => {
+      clipboardStore.entries.set([
+        makeEntry({ id: "1", source: "main.rs", content: "fn main() {}" }),
+        makeEntry({ id: "2", source: "app.ts", content: "const x = 1;" }),
+      ]);
+      clipboardStore.searchQuery.set("main.rs");
+      const filtered = get(clipboardStore.filteredEntries);
+      expect(filtered).toHaveLength(1);
+      expect(filtered[0].id).toBe("1");
+    });
+
+    it("returns all entries when search query is empty", () => {
+      clipboardStore.entries.set([makeEntry({ id: "1" }), makeEntry({ id: "2" })]);
+      clipboardStore.searchQuery.set("");
+      const filtered = get(clipboardStore.filteredEntries);
+      expect(filtered).toHaveLength(2);
+    });
+  });
+
+  describe("languages derived store", () => {
+    it("returns empty array when no entries", () => {
+      clipboardStore.entries.set([]);
+      expect(get(clipboardStore.languages)).toHaveLength(0);
+    });
+
+    it("returns unique sorted languages", () => {
+      clipboardStore.entries.set([
+        makeEntry({ language: "typescript" }),
+        makeEntry({ language: "python" }),
+        makeEntry({ language: "typescript" }),
+        makeEntry({ language: "rust" }),
+      ]);
+      const langs = get(clipboardStore.languages);
+      expect(langs).toEqual(["python", "rust", "typescript"]);
+    });
+
+    it("excludes entries with null language", () => {
+      clipboardStore.entries.set([
+        makeEntry({ language: "typescript" }),
+        makeEntry({ language: null }),
+      ]);
+      const langs = get(clipboardStore.languages);
+      expect(langs).toEqual(["typescript"]);
+    });
+  });
+});
+
+describe("clipboardStore - setSearchQuery and setLanguageFilter", () => {
+  it("setSearchQuery updates the searchQuery store", () => {
+    clipboardStore.setSearchQuery("hello world");
+    expect(get(clipboardStore.searchQuery)).toBe("hello world");
+    clipboardStore.setSearchQuery("");
+  });
+
+  it("setLanguageFilter updates the languageFilter store", () => {
+    clipboardStore.setLanguageFilter("python");
+    expect(get(clipboardStore.languageFilter)).toBe("python");
+    clipboardStore.setLanguageFilter(null);
+  });
+
+  it("setLanguageFilter can be reset to null", () => {
+    clipboardStore.setLanguageFilter("rust");
+    clipboardStore.setLanguageFilter(null);
+    expect(get(clipboardStore.languageFilter)).toBeNull();
+  });
+});
+
+describe("clipboardStore - store actions", () => {
+  const mockEntry = {
+    id: "entry-1",
+    content: "const x = 1;",
+    language: "typescript",
+    source: "test.ts",
+    timestamp: "2026-03-03T12:00:00.000Z",
+    is_pinned: false,
+  };
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    clipboardStore.entries.set([]);
+  });
+
+  describe("loadEntries", () => {
+    it("loads entries from backend and updates the store", async () => {
+      setMockInvokeResult("list_clipboard_entries", [mockEntry]);
+      await clipboardStore.loadEntries();
+      expect(get(clipboardStore.entries)).toEqual([mockEntry]);
+    });
+
+    it("handles errors gracefully without crashing", async () => {
+      const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      setMockInvokeResult("list_clipboard_entries", new Error("Backend unavailable"));
+      await clipboardStore.loadEntries();
+      expect(consoleErrorSpy).toHaveBeenCalledWith(
+        "Failed to load clipboard entries:",
+        expect.any(Error)
+      );
+      consoleErrorSpy.mockRestore();
+    });
+
+    it("sets isLoading to false after completion", async () => {
+      setMockInvokeResult("list_clipboard_entries", []);
+      await clipboardStore.loadEntries();
+      expect(get(clipboardStore.isLoading)).toBe(false);
+    });
+  });
+
+  describe("captureClipboard", () => {
+    it("captures clipboard entry with provided language", async () => {
+      setMockInvokeResult("capture_clipboard", mockEntry);
+      setMockInvokeResult("list_clipboard_entries", [mockEntry]);
+      const result = await clipboardStore.captureClipboard("const x = 1;", "typescript", "test.ts");
+      expect(result).toEqual(mockEntry);
+    });
+
+    it("auto-detects language when none provided", async () => {
+      setMockInvokeResult("capture_clipboard", mockEntry);
+      setMockInvokeResult("list_clipboard_entries", [mockEntry]);
+      const result = await clipboardStore.captureClipboard("const x = 1;");
+      expect(result).toEqual(mockEntry);
+    });
+
+    it("returns null on error", async () => {
+      const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      setMockInvokeResult("capture_clipboard", new Error("Failed"));
+      const result = await clipboardStore.captureClipboard("const x = 1;");
+      expect(result).toBeNull();
+      consoleErrorSpy.mockRestore();
+    });
+  });
+
+  describe("deleteEntry", () => {
+    it("removes entry from store on success", async () => {
+      clipboardStore.entries.set([mockEntry, { ...mockEntry, id: "entry-2" }]);
+      setMockInvokeResult("delete_clipboard_entry", undefined);
+      await clipboardStore.deleteEntry("entry-1");
+      expect(get(clipboardStore.entries)).toHaveLength(1);
+      expect(get(clipboardStore.entries)[0].id).toBe("entry-2");
+    });
+
+    it("handles errors gracefully", async () => {
+      const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      setMockInvokeResult("delete_clipboard_entry", new Error("Failed"));
+      await clipboardStore.deleteEntry("entry-1");
+      expect(consoleErrorSpy).toHaveBeenCalledWith(
+        "Failed to delete clipboard entry:",
+        expect.any(Error)
+      );
+      consoleErrorSpy.mockRestore();
+    });
+  });
+
+  describe("togglePin", () => {
+    it("updates entry pin status and sorts pinned first", async () => {
+      const unpinned1 = { ...mockEntry, id: "entry-1", is_pinned: false };
+      const unpinned2 = { ...mockEntry, id: "entry-2", is_pinned: false };
+      clipboardStore.entries.set([unpinned1, unpinned2]);
+      const pinned = { ...unpinned2, is_pinned: true };
+      setMockInvokeResult("toggle_pin_clipboard_entry", pinned);
+      await clipboardStore.togglePin("entry-2");
+      const entries = get(clipboardStore.entries);
+      expect(entries[0].id).toBe("entry-2");
+      expect(entries[0].is_pinned).toBe(true);
+    });
+
+    it("handles errors gracefully", async () => {
+      const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      setMockInvokeResult("toggle_pin_clipboard_entry", new Error("Failed"));
+      await clipboardStore.togglePin("entry-1");
+      expect(consoleErrorSpy).toHaveBeenCalledWith("Failed to toggle pin:", expect.any(Error));
+      consoleErrorSpy.mockRestore();
+    });
+
+    it("exercises the unpinned-before-pinned sort branch", async () => {
+      // Three entries so sort compares (entry-1 unpinned, entry-2 pinned) — hits line 144
+      const e1 = { ...mockEntry, id: "e1", is_pinned: false };
+      const e2 = { ...mockEntry, id: "e2", is_pinned: false };
+      const e3 = { ...mockEntry, id: "e3", is_pinned: false };
+      clipboardStore.entries.set([e1, e2, e3]);
+      const pinned = { ...e2, is_pinned: true };
+      setMockInvokeResult("toggle_pin_clipboard_entry", pinned);
+      await clipboardStore.togglePin("e2");
+      expect(get(clipboardStore.entries)[0].id).toBe("e2");
+    });
+
+    it("sorts same-pin-status entries by timestamp descending", async () => {
+      // Toggle entry to pinned while two others remain unpinned — sort compares unpinned pair by timestamp
+      const older = {
+        ...mockEntry,
+        id: "older",
+        is_pinned: false,
+        timestamp: "2026-01-01T00:00:00.000Z",
+      };
+      const newer = {
+        ...mockEntry,
+        id: "newer",
+        is_pinned: false,
+        timestamp: "2026-01-02T00:00:00.000Z",
+      };
+      const pinned = {
+        ...mockEntry,
+        id: "pinned",
+        is_pinned: false,
+        timestamp: "2026-01-03T00:00:00.000Z",
+      };
+      clipboardStore.entries.set([older, newer, pinned]);
+      const pinnedResult = { ...pinned, is_pinned: true };
+      setMockInvokeResult("toggle_pin_clipboard_entry", pinnedResult);
+      await clipboardStore.togglePin("pinned");
+      const entries = get(clipboardStore.entries);
+      expect(entries[0].id).toBe("pinned");
+      expect(entries[1].id).toBe("newer");
+      expect(entries[2].id).toBe("older");
+    });
+  });
+
+  describe("clearHistory", () => {
+    it("removes unpinned entries and keeps pinned ones", async () => {
+      const pinned = { ...mockEntry, id: "pinned", is_pinned: true };
+      const unpinned = { ...mockEntry, id: "unpinned", is_pinned: false };
+      clipboardStore.entries.set([pinned, unpinned]);
+      setMockInvokeResult("clear_clipboard_history", undefined);
+      await clipboardStore.clearHistory();
+      const entries = get(clipboardStore.entries);
+      expect(entries).toHaveLength(1);
+      expect(entries[0].id).toBe("pinned");
+    });
+
+    it("handles errors gracefully", async () => {
+      const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      setMockInvokeResult("clear_clipboard_history", new Error("Failed"));
+      await clipboardStore.clearHistory();
+      expect(consoleErrorSpy).toHaveBeenCalledWith(
+        "Failed to clear clipboard history:",
+        expect.any(Error)
+      );
+      consoleErrorSpy.mockRestore();
+    });
+  });
+
+  describe("updateLanguage", () => {
+    it("updates entry language in the store", async () => {
+      clipboardStore.entries.set([mockEntry]);
+      const updated = { ...mockEntry, language: "javascript" };
+      setMockInvokeResult("update_clipboard_language", updated);
+      await clipboardStore.updateLanguage("entry-1", "javascript");
+      expect(get(clipboardStore.entries)[0].language).toBe("javascript");
+    });
+
+    it("leaves non-matching entries unchanged", async () => {
+      const other = { ...mockEntry, id: "other", language: "python" };
+      clipboardStore.entries.set([mockEntry, other]);
+      const updated = { ...mockEntry, language: "javascript" };
+      setMockInvokeResult("update_clipboard_language", updated);
+      await clipboardStore.updateLanguage("entry-1", "javascript");
+      const entries = get(clipboardStore.entries);
+      expect(entries[1].language).toBe("python");
+    });
+
+    it("handles errors gracefully", async () => {
+      const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      setMockInvokeResult("update_clipboard_language", new Error("Failed"));
+      await clipboardStore.updateLanguage("entry-1", "javascript");
+      expect(consoleErrorSpy).toHaveBeenCalledWith("Failed to update language:", expect.any(Error));
+      consoleErrorSpy.mockRestore();
+    });
+  });
+
+  describe("copyToClipboard", () => {
+    it("returns true and copies text on success", async () => {
+      Object.assign(navigator, {
+        clipboard: { writeText: vi.fn().mockResolvedValue(undefined) },
+      });
+      const result = await clipboardStore.copyToClipboard("hello world");
+      expect(result).toBe(true);
+      expect(navigator.clipboard.writeText).toHaveBeenCalledWith("hello world");
+    });
+
+    it("returns false and logs error on failure", async () => {
+      const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      Object.assign(navigator, {
+        clipboard: { writeText: vi.fn().mockRejectedValue(new Error("Clipboard denied")) },
+      });
+      const result = await clipboardStore.copyToClipboard("hello world");
+      expect(result).toBe(false);
+      expect(consoleErrorSpy).toHaveBeenCalledWith(
+        "Failed to copy to clipboard:",
+        expect.any(Error)
+      );
+      consoleErrorSpy.mockRestore();
+    });
+  });
+});

src/lib/stores/config.test.ts

@@ -1,12 +1,20 @@
-import { describe, it, expect, beforeEach, vi } from "vitest";
+import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
+import { get } from "svelte/store";
 import {
   configStore,
   maskPaths,
   clampFontSize,
   applyFontSize,
+  applyCustomFont,
+  applyCustomUiFont,
   applyTheme,
   applyCustomThemeColors,
   clearCustomThemeColors,
+  isDarkTheme,
+  isStreamerMode,
+  isCompactMode,
+  shouldHidePaths,
+  showThinkingBlocks,
   MIN_FONT_SIZE,
   MAX_FONT_SIZE,
   DEFAULT_FONT_SIZE,
@@ -15,12 +23,17 @@ import {
   type CustomThemeColors,
 } from "./config";
 import { invoke } from "@tauri-apps/api/core";
+import { readFile } from "@tauri-apps/plugin-fs";
 
 // Mock Tauri APIs
 vi.mock("@tauri-apps/api/core", () => ({
   invoke: vi.fn(),
 }));
 
+vi.mock("@tauri-apps/plugin-fs", () => ({
+  readFile: vi.fn(),
+}));
+
 describe("config store", () => {
   describe("font size constants", () => {
     it("has correct MIN_FONT_SIZE", () => {
@@ -196,9 +209,14 @@ describe("config store", () => {
         show_thinking_blocks: true,
         use_worktree: false,
         disable_1m_context: false,
+        max_output_tokens: null,
         trusted_workspaces: [],
         background_image_path: null,
         background_image_opacity: 0.3,
+        custom_font_path: null,
+        custom_font_family: null,
+        custom_ui_font_path: null,
+        custom_ui_font_family: null,
       };
 
       expect(config.model).toBe("claude-sonnet-4");
@@ -247,9 +265,14 @@ describe("config store", () => {
         show_thinking_blocks: true,
         use_worktree: false,
         disable_1m_context: false,
+        max_output_tokens: null,
         trusted_workspaces: [],
         background_image_path: null,
         background_image_opacity: 0.3,
+        custom_font_path: null,
+        custom_font_family: null,
+        custom_ui_font_path: null,
+        custom_ui_font_family: null,
       };
 
       expect(config.model).toBeNull();
@@ -797,9 +820,14 @@ describe("config store", () => {
         show_thinking_blocks: true,
         use_worktree: false,
         disable_1m_context: false,
+        max_output_tokens: null,
         trusted_workspaces: [],
         background_image_path: null,
         background_image_opacity: 0.3,
+        custom_font_path: null,
+        custom_font_family: null,
+        custom_ui_font_path: null,
+        custom_ui_font_family: null,
       };
 
       const mockInvokeImpl = vi.mocked(invoke);
@@ -840,4 +868,607 @@ describe("config store", () => {
       expect(lastSaved.font_size).toBe(16);
     });
   });
+
+  describe("loadConfig error path", () => {
+    it("resets to default config and logs error when loadConfig fails", async () => {
+      vi.mocked(invoke).mockResolvedValue(null);
+      await configStore.updateConfig({ theme: "light" });
+
+      const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      vi.mocked(invoke).mockRejectedValue(new Error("Backend unavailable"));
+
+      await configStore.loadConfig();
+
+      expect(configStore.getConfig().theme).toBe("dark");
+      expect(consoleErrorSpy).toHaveBeenCalledWith("Failed to load config:", expect.any(Error));
+      consoleErrorSpy.mockRestore();
+    });
+  });
+
+  describe("configStore sidebar methods", () => {
+    it("openSidebar sets isSidebarOpen to true", () => {
+      configStore.closeSidebar();
+      configStore.openSidebar();
+      expect(get(configStore.isSidebarOpen)).toBe(true);
+    });
+
+    it("closeSidebar sets isSidebarOpen to false", () => {
+      configStore.openSidebar();
+      configStore.closeSidebar();
+      expect(get(configStore.isSidebarOpen)).toBe(false);
+    });
+
+    it("toggleSidebar switches from false to true", () => {
+      configStore.closeSidebar();
+      configStore.toggleSidebar();
+      expect(get(configStore.isSidebarOpen)).toBe(true);
+    });
+
+    it("toggleSidebar switches from true to false", () => {
+      configStore.openSidebar();
+      configStore.toggleSidebar();
+      expect(get(configStore.isSidebarOpen)).toBe(false);
+    });
+  });
+
+  describe("configStore setTheme method", () => {
+    beforeEach(async () => {
+      vi.mocked(invoke).mockResolvedValue(null);
+    });
+
+    afterEach(() => {
+      vi.resetAllMocks();
+    });
+
+    it("setTheme updates the theme via invoke", async () => {
+      await configStore.setTheme("light");
+      expect(configStore.getConfig().theme).toBe("light");
+    });
+
+    it("setTheme with custom colors updates custom_theme_colors", async () => {
+      const colors: CustomThemeColors = {
+        bg_primary: "#001122",
+        bg_secondary: null,
+        bg_terminal: null,
+        accent_primary: null,
+        accent_secondary: null,
+        text_primary: null,
+        text_secondary: null,
+        border_color: null,
+      };
+
+      await configStore.setTheme("custom", colors);
+
+      expect(configStore.getConfig().theme).toBe("custom");
+      expect(configStore.getConfig().custom_theme_colors.bg_primary).toBe("#001122");
+    });
+  });
+
+  describe("configStore setCustomThemeColors with custom theme active", () => {
+    beforeEach(async () => {
+      vi.mocked(invoke).mockResolvedValue(null);
+      await configStore.setTheme("custom");
+    });
+
+    afterEach(() => {
+      vi.resetAllMocks();
+      clearCustomThemeColors();
+    });
+
+    it("applies custom colors to DOM when current theme is custom", async () => {
+      const colors: CustomThemeColors = {
+        bg_primary: "#aabbcc",
+        bg_secondary: null,
+        bg_terminal: null,
+        accent_primary: null,
+        accent_secondary: null,
+        text_primary: null,
+        text_secondary: null,
+        border_color: null,
+      };
+
+      await configStore.setCustomThemeColors(colors);
+
+      expect(document.documentElement.style.getPropertyValue("--bg-primary")).toBe("#aabbcc");
+    });
+  });
+
+  describe("configStore font size methods", () => {
+    beforeEach(async () => {
+      vi.mocked(invoke).mockResolvedValue(null);
+      await configStore.updateConfig({ font_size: DEFAULT_FONT_SIZE });
+      vi.resetAllMocks();
+      vi.mocked(invoke).mockResolvedValue(null);
+    });
+
+    afterEach(() => {
+      vi.resetAllMocks();
+    });
+
+    it("setFontSize updates to the given value", async () => {
+      await configStore.setFontSize(18);
+      expect(configStore.getConfig().font_size).toBe(18);
+    });
+
+    it("setFontSize clamps to minimum", async () => {
+      await configStore.setFontSize(1);
+      expect(configStore.getConfig().font_size).toBe(MIN_FONT_SIZE);
+    });
+
+    it("setFontSize clamps to maximum", async () => {
+      await configStore.setFontSize(99);
+      expect(configStore.getConfig().font_size).toBe(MAX_FONT_SIZE);
+    });
+
+    it("increaseFontSize increases font size by 2", async () => {
+      await configStore.increaseFontSize();
+      expect(configStore.getConfig().font_size).toBe(DEFAULT_FONT_SIZE + 2);
+    });
+
+    it("increaseFontSize does not exceed maximum", async () => {
+      await configStore.setFontSize(MAX_FONT_SIZE);
+      await configStore.increaseFontSize();
+      expect(configStore.getConfig().font_size).toBe(MAX_FONT_SIZE);
+    });
+
+    it("decreaseFontSize decreases font size by 2", async () => {
+      await configStore.decreaseFontSize();
+      expect(configStore.getConfig().font_size).toBe(DEFAULT_FONT_SIZE - 2);
+    });
+
+    it("decreaseFontSize does not go below minimum", async () => {
+      await configStore.setFontSize(MIN_FONT_SIZE);
+      await configStore.decreaseFontSize();
+      expect(configStore.getConfig().font_size).toBe(MIN_FONT_SIZE);
+    });
+
+    it("resetFontSize restores the default font size", async () => {
+      await configStore.setFontSize(20);
+      await configStore.resetFontSize();
+      expect(configStore.getConfig().font_size).toBe(DEFAULT_FONT_SIZE);
+    });
+  });
+
+  describe("configStore removeAutoGrantedTool", () => {
+    beforeEach(async () => {
+      vi.mocked(invoke).mockResolvedValue(null);
+      await configStore.updateConfig({ auto_granted_tools: [] });
+      vi.resetAllMocks();
+      vi.mocked(invoke).mockResolvedValue(null);
+    });
+
+    afterEach(() => {
+      vi.resetAllMocks();
+    });
+
+    it("removes an existing tool", async () => {
+      await configStore.addAutoGrantedTool("Bash");
+      await configStore.removeAutoGrantedTool("Bash");
+      expect(configStore.getConfig().auto_granted_tools).not.toContain("Bash");
+    });
+
+    it("is a no-op when the tool is not in the list", async () => {
+      await configStore.removeAutoGrantedTool("NonExistentTool");
+      expect(configStore.getConfig().auto_granted_tools).toEqual([]);
+    });
+  });
+
+  describe("configStore toggle methods", () => {
+    beforeEach(async () => {
+      vi.mocked(invoke).mockResolvedValue(null);
+      await configStore.updateConfig({ streamer_mode: false, compact_mode: false });
+      vi.resetAllMocks();
+      vi.mocked(invoke).mockResolvedValue(null);
+    });
+
+    afterEach(() => {
+      vi.resetAllMocks();
+    });
+
+    it("toggleStreamerMode flips streamer_mode from false to true", async () => {
+      await configStore.toggleStreamerMode();
+      expect(configStore.getConfig().streamer_mode).toBe(true);
+    });
+
+    it("toggleStreamerMode flips streamer_mode from true to false", async () => {
+      await configStore.updateConfig({ streamer_mode: true });
+      await configStore.toggleStreamerMode();
+      expect(configStore.getConfig().streamer_mode).toBe(false);
+    });
+
+    it("toggleCompactMode flips compact_mode from false to true", async () => {
+      await configStore.toggleCompactMode();
+      expect(configStore.getConfig().compact_mode).toBe(true);
+    });
+
+    it("toggleCompactMode flips compact_mode from true to false", async () => {
+      await configStore.updateConfig({ compact_mode: true });
+      await configStore.toggleCompactMode();
+      expect(configStore.getConfig().compact_mode).toBe(false);
+    });
+
+    it("setCompactMode enables compact mode", async () => {
+      await configStore.setCompactMode(true);
+      expect(configStore.getConfig().compact_mode).toBe(true);
+    });
+
+    it("setCompactMode disables compact mode", async () => {
+      await configStore.updateConfig({ compact_mode: true });
+      await configStore.setCompactMode(false);
+      expect(configStore.getConfig().compact_mode).toBe(false);
+    });
+  });
+
+  describe("derived stores (live subscriptions)", () => {
+    beforeEach(async () => {
+      vi.mocked(invoke).mockResolvedValue(null);
+    });
+
+    afterEach(() => {
+      vi.resetAllMocks();
+    });
+
+    it("isDarkTheme is true when theme is dark", async () => {
+      await configStore.updateConfig({ theme: "dark" });
+      expect(get(isDarkTheme)).toBe(true);
+    });
+
+    it("isDarkTheme is false when theme is not dark", async () => {
+      await configStore.updateConfig({ theme: "light" });
+      expect(get(isDarkTheme)).toBe(false);
+    });
+
+    it("isStreamerMode reflects streamer_mode config", async () => {
+      await configStore.updateConfig({ streamer_mode: true });
+      expect(get(isStreamerMode)).toBe(true);
+      await configStore.updateConfig({ streamer_mode: false });
+      expect(get(isStreamerMode)).toBe(false);
+    });
+
+    it("isCompactMode reflects compact_mode config", async () => {
+      await configStore.updateConfig({ compact_mode: true });
+      expect(get(isCompactMode)).toBe(true);
+      await configStore.updateConfig({ compact_mode: false });
+      expect(get(isCompactMode)).toBe(false);
+    });
+
+    it("shouldHidePaths is true when both streamer flags are enabled", async () => {
+      await configStore.updateConfig({ streamer_mode: true, streamer_hide_paths: true });
+      expect(get(shouldHidePaths)).toBe(true);
+    });
+
+    it("shouldHidePaths is false when streamer_mode is disabled", async () => {
+      await configStore.updateConfig({ streamer_mode: false, streamer_hide_paths: true });
+      expect(get(shouldHidePaths)).toBe(false);
+    });
+
+    it("showThinkingBlocks is true when show_thinking_blocks is enabled", async () => {
+      await configStore.updateConfig({ show_thinking_blocks: true });
+      expect(get(showThinkingBlocks)).toBe(true);
+    });
+
+    it("showThinkingBlocks is false when show_thinking_blocks is disabled", async () => {
+      await configStore.updateConfig({ show_thinking_blocks: false });
+      expect(get(showThinkingBlocks)).toBe(false);
+    });
+  });
+
+  describe("applyCustomFont", () => {
+    const readFileMock = vi.mocked(readFile);
+
+    beforeEach(() => {
+      // Remove any style element left by previous tests
+      document.getElementById("hikari-custom-font")?.remove();
+      document.documentElement.style.removeProperty("--terminal-font-family");
+      readFileMock.mockReset();
+    });
+
+    it("removes CSS variable when both path and family are null", async () => {
+      document.documentElement.style.setProperty("--terminal-font-family", "'SomeFont', monospace");
+      await applyCustomFont(null, null);
+      expect(document.documentElement.style.getPropertyValue("--terminal-font-family")).toBe("");
+    });
+
+    it("removes CSS variable when both path and family are empty strings", async () => {
+      document.documentElement.style.setProperty("--terminal-font-family", "'SomeFont', monospace");
+      await applyCustomFont("", "");
+      expect(document.documentElement.style.getPropertyValue("--terminal-font-family")).toBe("");
+      expect(document.getElementById("hikari-custom-font")).toBeNull();
+    });
+
+    it("injects @import for a CSS stylesheet URL", async () => {
+      await applyCustomFont("https://fonts.googleapis.com/css2?family=Fira+Code", "Fira Code");
+      const style = document.getElementById("hikari-custom-font");
+      expect(style).not.toBeNull();
+      expect(style?.textContent).toContain(
+        "@import url('https://fonts.googleapis.com/css2?family=Fira+Code')"
+      );
+      expect(document.documentElement.style.getPropertyValue("--terminal-font-family")).toBe(
+        "'Fira Code', monospace"
+      );
+    });
+
+    it("injects @font-face for a direct font file URL (.woff2)", async () => {
+      await applyCustomFont("https://example.com/fonts/myfont.woff2", "MyFont");
+      const style = document.getElementById("hikari-custom-font");
+      expect(style).not.toBeNull();
+      expect(style?.textContent).toContain("@font-face");
+      expect(style?.textContent).toContain("url('https://example.com/fonts/myfont.woff2')");
+      expect(style?.textContent).toContain("'MyFont'");
+      expect(document.documentElement.style.getPropertyValue("--terminal-font-family")).toBe(
+        "'MyFont', monospace"
+      );
+    });
+
+    it("injects @font-face for a direct font file URL (.ttf)", async () => {
+      await applyCustomFont("https://example.com/fonts/myfont.ttf", "MyTtfFont");
+      const style = document.getElementById("hikari-custom-font");
+      expect(style).not.toBeNull();
+      expect(style?.textContent).toContain("@font-face");
+      expect(style?.textContent).toContain("url('https://example.com/fonts/myfont.ttf')");
+      expect(style?.textContent).toContain("'MyTtfFont'");
+    });
+
+    it("uses HikariCustomFont as fallback family for direct font URLs when family is empty", async () => {
+      await applyCustomFont("https://example.com/fonts/myfont.woff2", "");
+      const style = document.getElementById("hikari-custom-font");
+      expect(style?.textContent).toContain("'HikariCustomFont'");
+    });
+
+    it("reads local file and injects @font-face with data URL", async () => {
+      const fakeData = new Uint8Array([72, 101, 108, 108, 111]); // "Hello"
+      readFileMock.mockResolvedValueOnce(fakeData);
+
+      await applyCustomFont("/home/naomi/.fonts/MyFont.ttf", "MyFont");
+
+      expect(readFileMock).toHaveBeenCalledWith("/home/naomi/.fonts/MyFont.ttf");
+      const style = document.getElementById("hikari-custom-font");
+      expect(style).not.toBeNull();
+      expect(style?.textContent).toContain("@font-face");
+      expect(style?.textContent).toContain("data:font/ttf;base64,");
+      expect(style?.textContent).toContain("'MyFont'");
+      expect(document.documentElement.style.getPropertyValue("--terminal-font-family")).toBe(
+        "'MyFont', monospace"
+      );
+    });
+
+    it("uses HikariCustomFont as fallback family for local files when family is empty", async () => {
+      const fakeData = new Uint8Array([1, 2, 3]);
+      readFileMock.mockResolvedValueOnce(fakeData);
+
+      await applyCustomFont("/home/naomi/.fonts/MyFont.woff2", "");
+
+      const style = document.getElementById("hikari-custom-font");
+      expect(style?.textContent).toContain("'HikariCustomFont'");
+      expect(style?.textContent).toContain("font/woff2");
+    });
+
+    it("sets CSS variable when only family is provided (no path)", async () => {
+      await applyCustomFont("", "SystemFont");
+      expect(document.documentElement.style.getPropertyValue("--terminal-font-family")).toBe(
+        "'SystemFont', monospace"
+      );
+      expect(document.getElementById("hikari-custom-font")).toBeNull();
+    });
+
+    it("replaces a previously injected style element", async () => {
+      await applyCustomFont("https://fonts.googleapis.com/css2?family=Fira+Code", "Fira Code");
+      expect(document.getElementById("hikari-custom-font")).not.toBeNull();
+
+      await applyCustomFont("https://fonts.googleapis.com/css2?family=Roboto+Mono", "Roboto Mono");
+      const styles = document.querySelectorAll("#hikari-custom-font");
+      expect(styles.length).toBe(1);
+      expect(styles[0].textContent).toContain("Roboto+Mono");
+    });
+
+    it("uses correct MIME type for .otf local files", async () => {
+      readFileMock.mockResolvedValueOnce(new Uint8Array([1]));
+      await applyCustomFont("/fonts/MyFont.otf", "OtfFont");
+      const style = document.getElementById("hikari-custom-font");
+      expect(style?.textContent).toContain("font/otf");
+    });
+
+    it("falls back to font/ttf MIME for unknown extension local files", async () => {
+      readFileMock.mockResolvedValueOnce(new Uint8Array([1]));
+      await applyCustomFont("/fonts/MyFont.xyz", "XyzFont");
+      const style = document.getElementById("hikari-custom-font");
+      expect(style?.textContent).toContain("font/ttf");
+    });
+  });
+
+  describe("setCustomFont", () => {
+    const readFileMock = vi.mocked(readFile);
+    const invokeMock = vi.mocked(invoke);
+
+    beforeEach(() => {
+      document.getElementById("hikari-custom-font")?.remove();
+      document.documentElement.style.removeProperty("--terminal-font-family");
+      readFileMock.mockReset();
+      invokeMock.mockResolvedValue(undefined);
+    });
+
+    it("saves config and applies the font", async () => {
+      await configStore.setCustomFont(null, null);
+      await configStore.setCustomFont(
+        "https://fonts.googleapis.com/css2?family=Fira+Code",
+        "Fira Code"
+      );
+
+      expect(invokeMock).toHaveBeenCalledWith(
+        "save_config",
+        expect.objectContaining({
+          config: expect.objectContaining({
+            custom_font_path: "https://fonts.googleapis.com/css2?family=Fira+Code",
+            custom_font_family: "Fira Code",
+          }),
+        })
+      );
+      expect(document.documentElement.style.getPropertyValue("--terminal-font-family")).toBe(
+        "'Fira Code', monospace"
+      );
+    });
+
+    it("clears font when called with nulls", async () => {
+      document.documentElement.style.setProperty("--terminal-font-family", "'SomeFont', monospace");
+      await configStore.setCustomFont(null, null);
+
+      expect(document.documentElement.style.getPropertyValue("--terminal-font-family")).toBe("");
+      expect(invokeMock).toHaveBeenCalledWith(
+        "save_config",
+        expect.objectContaining({
+          config: expect.objectContaining({
+            custom_font_path: null,
+            custom_font_family: null,
+          }),
+        })
+      );
+    });
+  });
+
+  describe("applyCustomUiFont", () => {
+    const readFileMock = vi.mocked(readFile);
+
+    beforeEach(() => {
+      document.getElementById("hikari-custom-ui-font")?.remove();
+      document.documentElement.style.removeProperty("--ui-font-family");
+      document.body.style.removeProperty("font-family");
+      readFileMock.mockReset();
+    });
+
+    it("removes CSS variable and body font-family when both path and family are null", async () => {
+      document.documentElement.style.setProperty("--ui-font-family", "'SomeFont', sans-serif");
+      document.body.style.setProperty("font-family", "'SomeFont', sans-serif");
+      await applyCustomUiFont(null, null);
+      expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe("");
+      expect(document.body.style.getPropertyValue("font-family")).toBe("");
+    });
+
+    it("removes CSS variable and body font-family when both path and family are empty strings", async () => {
+      document.documentElement.style.setProperty("--ui-font-family", "'SomeFont', sans-serif");
+      document.body.style.setProperty("font-family", "'SomeFont', sans-serif");
+      await applyCustomUiFont("", "");
+      expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe("");
+      expect(document.body.style.getPropertyValue("font-family")).toBe("");
+      expect(document.getElementById("hikari-custom-ui-font")).toBeNull();
+    });
+
+    it("injects @import for a CSS stylesheet URL and applies font to body", async () => {
+      await applyCustomUiFont("https://fonts.googleapis.com/css2?family=Inter", "Inter");
+      const style = document.getElementById("hikari-custom-ui-font");
+      expect(style).not.toBeNull();
+      expect(style?.textContent).toContain(
+        "@import url('https://fonts.googleapis.com/css2?family=Inter')"
+      );
+      expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe(
+        "'Inter', sans-serif"
+      );
+      expect(document.body.style.getPropertyValue("font-family")).toBe('"Inter", sans-serif');
+    });
+
+    it("injects @font-face for a direct font file URL (.woff2) and applies font to body", async () => {
+      await applyCustomUiFont("https://example.com/fonts/Inter.woff2", "Inter");
+      const style = document.getElementById("hikari-custom-ui-font");
+      expect(style).not.toBeNull();
+      expect(style?.textContent).toContain("@font-face");
+      expect(style?.textContent).toContain("url('https://example.com/fonts/Inter.woff2')");
+      expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe(
+        "'Inter', sans-serif"
+      );
+      expect(document.body.style.getPropertyValue("font-family")).toBe('"Inter", sans-serif');
+    });
+
+    it("uses HikariCustomUiFont as fallback family and applies it to body", async () => {
+      await applyCustomUiFont("https://example.com/fonts/Inter.woff2", "");
+      const style = document.getElementById("hikari-custom-ui-font");
+      expect(style?.textContent).toContain("'HikariCustomUiFont'");
+      expect(document.body.style.getPropertyValue("font-family")).toBe(
+        '"HikariCustomUiFont", sans-serif'
+      );
+    });
+
+    it("reads local file and embeds as data URL, applies font to body", async () => {
+      const fakeData = new Uint8Array([104, 101, 108, 108, 111]);
+      readFileMock.mockResolvedValueOnce(fakeData);
+
+      await applyCustomUiFont("/home/naomi/.fonts/Inter.ttf", "Inter");
+
+      expect(readFileMock).toHaveBeenCalledWith("/home/naomi/.fonts/Inter.ttf");
+      const style = document.getElementById("hikari-custom-ui-font");
+      expect(style?.textContent).toContain("data:font/ttf;base64,");
+      expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe(
+        "'Inter', sans-serif"
+      );
+      expect(document.body.style.getPropertyValue("font-family")).toBe('"Inter", sans-serif');
+    });
+
+    it("sets CSS variable and body font-family when only family is provided (no path)", async () => {
+      await applyCustomUiFont("", "SystemUiFont");
+      expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe(
+        "'SystemUiFont', sans-serif"
+      );
+      expect(document.body.style.getPropertyValue("font-family")).toBe(
+        '"SystemUiFont", sans-serif'
+      );
+    });
+
+    it("replaces a previously injected style element", async () => {
+      await applyCustomUiFont("https://fonts.googleapis.com/css2?family=Inter", "Inter");
+      expect(document.getElementById("hikari-custom-ui-font")).not.toBeNull();
+
+      await applyCustomUiFont("https://fonts.googleapis.com/css2?family=Roboto", "Roboto");
+      const styles = document.querySelectorAll("#hikari-custom-ui-font");
+      expect(styles.length).toBe(1);
+      expect(styles[0].textContent).toContain("Roboto");
+    });
+  });
+
+  describe("setCustomUiFont", () => {
+    const readFileMock = vi.mocked(readFile);
+    const invokeMock = vi.mocked(invoke);
+
+    beforeEach(() => {
+      document.getElementById("hikari-custom-ui-font")?.remove();
+      document.documentElement.style.removeProperty("--ui-font-family");
+      document.body.style.removeProperty("font-family");
+      readFileMock.mockReset();
+      invokeMock.mockResolvedValue(undefined);
+    });
+
+    it("saves config and applies the UI font", async () => {
+      await configStore.setCustomUiFont(null, null);
+      await configStore.setCustomUiFont("https://fonts.googleapis.com/css2?family=Inter", "Inter");
+
+      expect(invokeMock).toHaveBeenCalledWith(
+        "save_config",
+        expect.objectContaining({
+          config: expect.objectContaining({
+            custom_ui_font_path: "https://fonts.googleapis.com/css2?family=Inter",
+            custom_ui_font_family: "Inter",
+          }),
+        })
+      );
+      expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe(
+        "'Inter', sans-serif"
+      );
+      expect(document.body.style.getPropertyValue("font-family")).toBe('"Inter", sans-serif');
+    });
+
+    it("clears UI font when called with nulls", async () => {
+      document.documentElement.style.setProperty("--ui-font-family", "'SomeFont', sans-serif");
+      document.body.style.setProperty("font-family", "'SomeFont', sans-serif");
+      await configStore.setCustomUiFont(null, null);
+
+      expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe("");
+      expect(document.body.style.getPropertyValue("font-family")).toBe("");
+      expect(invokeMock).toHaveBeenCalledWith(
+        "save_config",
+        expect.objectContaining({
+          config: expect.objectContaining({
+            custom_ui_font_path: null,
+            custom_ui_font_family: null,
+          }),
+        })
+      );
+    });
+  });
 });

src/lib/stores/config.ts

@@ -1,5 +1,6 @@
 import { writable, derived } from "svelte/store";
 import { invoke } from "@tauri-apps/api/core";
+import { readFile } from "@tauri-apps/plugin-fs";
 
 export type Theme = "dark" | "light" | "high-contrast" | "custom";
 export type BudgetAction = "warn" | "block";
@@ -51,11 +52,19 @@ export interface HikariConfig {
   use_worktree: boolean;
   // Disable 1M context window
   disable_1m_context: boolean;
+  // Max output tokens for Claude Code responses
+  max_output_tokens: number | null;
   // Workspaces the user has explicitly trusted
   trusted_workspaces: string[];
   // Background image settings
   background_image_path: string | null;
   background_image_opacity: number;
+  // Custom terminal font settings
+  custom_font_path: string | null;
+  custom_font_family: string | null;
+  // Custom UI font settings
+  custom_ui_font_path: string | null;
+  custom_ui_font_family: string | null;
 }
 
 const defaultConfig: HikariConfig = {
@@ -98,9 +107,14 @@ const defaultConfig: HikariConfig = {
   show_thinking_blocks: true,
   use_worktree: false,
   disable_1m_context: false,
+  max_output_tokens: null,
   trusted_workspaces: [],
   background_image_path: null,
   background_image_opacity: 0.3,
+  custom_font_path: null,
+  custom_font_family: null,
+  custom_ui_font_path: null,
+  custom_ui_font_family: null,
 };
 
 function createConfigStore() {
@@ -237,6 +251,16 @@ function createConfigStore() {
     setCompactMode: async (enabled: boolean) => {
       await updateConfig({ compact_mode: enabled });
     },
+
+    setCustomFont: async (path: string | null, family: string | null) => {
+      await updateConfig({ custom_font_path: path, custom_font_family: family });
+      await applyCustomFont(path, family);
+    },
+
+    setCustomUiFont: async (path: string | null, family: string | null) => {
+      await updateConfig({ custom_ui_font_path: path, custom_ui_font_family: family });
+      await applyCustomUiFont(path, family);
+    },
   };
 }
 
@@ -302,6 +326,99 @@ export function clampFontSize(size: number): number {
   return Math.max(MIN_FONT_SIZE, Math.min(MAX_FONT_SIZE, size));
 }
 
+const DIRECT_FONT_EXTENSIONS = new Set(["woff", "woff2", "ttf", "otf", "eot"]);
+
+const FONT_MIME_MAP: Record<string, string> = {
+  woff: "font/woff",
+  woff2: "font/woff2",
+  ttf: "font/ttf",
+  otf: "font/otf",
+  eot: "application/vnd.ms-fontobject",
+};
+
+async function applyFontFromSource(path: string, family: string, styleId: string): Promise<void> {
+  const style = document.createElement("style");
+  style.id = styleId;
+
+  if (path.startsWith("http://") || path.startsWith("https://")) {
+    const ext = path.split(".").pop()?.toLowerCase() ?? "";
+
+    if (DIRECT_FONT_EXTENSIONS.has(ext)) {
+      style.textContent = `@font-face { font-family: '${family}'; src: url('${path}'); }`;
+    } else {
+      style.textContent = `@import url('${path}');`;
+    }
+  } else {
+    const data = await readFile(path);
+    const chunks: string[] = [];
+    const chunkSize = 8192;
+    for (let i = 0; i < data.length; i += chunkSize) {
+      chunks.push(String.fromCharCode(...data.slice(i, i + chunkSize)));
+    }
+    const ext = path.split(".").pop()?.toLowerCase() ?? "ttf";
+    const mime = FONT_MIME_MAP[ext] ?? "font/ttf";
+    const dataUrl = `data:${mime};base64,${btoa(chunks.join(""))}`;
+    style.textContent = `@font-face { font-family: '${family}'; src: url('${dataUrl}'); }`;
+  }
+
+  document.head.appendChild(style);
+}
+
+export async function applyCustomFont(path: string | null, family: string | null): Promise<void> {
+  if (typeof document === "undefined") return;
+
+  const styleId = "hikari-custom-font";
+  const cssVar = "--terminal-font-family";
+  const fallbackFamily = "HikariCustomFont";
+
+  document.getElementById(styleId)?.remove();
+
+  const trimmedPath = path?.trim() ?? "";
+  const trimmedFamily = family?.trim() ?? "";
+
+  if (!trimmedPath && !trimmedFamily) {
+    document.documentElement.style.removeProperty(cssVar);
+    return;
+  }
+
+  if (trimmedPath) {
+    await applyFontFromSource(trimmedPath, trimmedFamily || fallbackFamily, styleId);
+  }
+
+  if (trimmedFamily) {
+    document.documentElement.style.setProperty(cssVar, `'${trimmedFamily}', monospace`);
+  }
+}
+
+export async function applyCustomUiFont(path: string | null, family: string | null): Promise<void> {
+  if (typeof document === "undefined") return;
+
+  const styleId = "hikari-custom-ui-font";
+  const cssVar = "--ui-font-family";
+  const fallbackFamily = "HikariCustomUiFont";
+
+  document.getElementById(styleId)?.remove();
+
+  const trimmedPath = path?.trim() ?? "";
+  const trimmedFamily = family?.trim() ?? "";
+
+  if (!trimmedPath && !trimmedFamily) {
+    document.documentElement.style.removeProperty(cssVar);
+    document.body?.style.removeProperty("font-family");
+    return;
+  }
+
+  const effectiveFamily = trimmedFamily || fallbackFamily;
+
+  if (trimmedPath) {
+    await applyFontFromSource(trimmedPath, effectiveFamily, styleId);
+  }
+
+  const fontValue = `'${effectiveFamily}', sans-serif`;
+  document.documentElement.style.setProperty(cssVar, fontValue);
+  document.body?.style.setProperty("font-family", fontValue);
+}
+
 export { MIN_FONT_SIZE, MAX_FONT_SIZE, DEFAULT_FONT_SIZE };
 
 export const configStore = createConfigStore();

src/lib/stores/conversations.ts

@@ -43,6 +43,88 @@ export interface Conversation {
   draftText: string;
 }
 
+const TAB_NAMES = [
+  // Cosmic & celestial
+  "Starfall",
+  "Moonbeam",
+  "Nebula",
+  "Aurora",
+  "Stardust",
+  "Solstice",
+  "Comet",
+  "Eclipse",
+  "Zenith",
+  "Celestia",
+  "Nova",
+  "Quasar",
+  "Lyra",
+  "Andromeda",
+  "Twilight",
+  // Magical & fantastical
+  "Camelot",
+  "Reverie",
+  "Arcane",
+  "Spellbound",
+  "Mirage",
+  "Oracle",
+  "Seraphim",
+  "Ethereal",
+  "Labyrinth",
+  "Enchantment",
+  // Nature & cosy
+  "Sakura",
+  "Ember",
+  "Cascade",
+  "Zephyr",
+  "Serendipity",
+  "Solace",
+  "Blossom",
+  "Whisper",
+  "Dewdrop",
+  "Sunbeam",
+  "Willow",
+  "Clover",
+  "Honeybee",
+  "Buttercup",
+  "Dandelion",
+  // Japanese/anime-inspired
+  "Tsukimi",
+  "Hanami",
+  "Yozora",
+  "Hoshi",
+  "Koharu",
+  "Akari",
+  "Midori",
+  // Adventure & epic
+  "Odyssey",
+  "Wanderer",
+  "Horizon",
+  "Voyage",
+  "Pathfinder",
+  "Frontier",
+  // Whimsical & sweet
+  "Bubblegum",
+  "Marshmallow",
+  "Daydream",
+  "Whimsy",
+  "Jellybean",
+  "Sprinkle",
+  "Cupcake",
+  // Dreamy & poetic
+  "Revenant",
+  "Elysium",
+  "Halcyon",
+  "Ephemera",
+  "Serenade",
+  "Lullaby",
+  "Nocturne",
+  "Rhapsody",
+];
+
+function pickRandomTabName(): string {
+  return TAB_NAMES[Math.floor(Math.random() * TAB_NAMES.length)];
+}
+
 function createConversationsStore() {
   const conversations = writable<Map<string, Conversation>>(new Map());
   const activeConversationId = writable<string | null>(null);
@@ -63,7 +145,7 @@ function createConversationsStore() {
     const id = generateConversationId();
     return {
       id,
-      name: name || `Conversation ${conversationCounter}`,
+      name: name ?? pickRandomTabName(),
       terminalLines: [],
       sessionId: null,
       connectionStatus: "disconnected",
@@ -91,7 +173,7 @@ function createConversationsStore() {
   function ensureInitialized() {
     if (!initialized) {
       initialized = true;
-      const initialConversation = createNewConversation("Main");
+      const initialConversation = createNewConversation();
       conversations.update((convs) => {
         convs.set(initialConversation.id, initialConversation);
         return convs;

src/lib/stores/costTracking.test.ts

@@ -0,0 +1,292 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { get } from "svelte/store";
+import { invoke } from "@tauri-apps/api/core";
+import { setMockInvokeResult } from "../../../vitest.setup";
+import {
+  formatCost,
+  formatAlertType,
+  getAlertMessage,
+  costTrackingStore,
+  formattedCosts,
+  type AlertType,
+  type CostAlert,
+} from "./costTracking";
+
+vi.mock("$lib/notifications/notificationManager", () => ({
+  notificationManager: {
+    notifyCostAlert: vi.fn(),
+  },
+}));
+
+describe("formatCost", () => {
+  it("formats amounts below $0.01 to 4 decimal places", () => {
+    expect(formatCost(0)).toBe("$0.0000");
+    expect(formatCost(0.001)).toBe("$0.0010");
+    expect(formatCost(0.0099)).toBe("$0.0099");
+  });
+
+  it("formats amounts between $0.01 and $1 to 3 decimal places", () => {
+    expect(formatCost(0.01)).toBe("$0.010");
+    expect(formatCost(0.123)).toBe("$0.123");
+    expect(formatCost(0.999)).toBe("$0.999");
+  });
+
+  it("formats amounts $1 and above to 2 decimal places", () => {
+    expect(formatCost(1)).toBe("$1.00");
+    expect(formatCost(1.5)).toBe("$1.50");
+    expect(formatCost(100.99)).toBe("$100.99");
+  });
+});
+
+describe("formatAlertType", () => {
+  it("formats Daily as Today", () => {
+    expect(formatAlertType("Daily")).toBe("Today");
+  });
+
+  it("formats Weekly as This Week", () => {
+    expect(formatAlertType("Weekly")).toBe("This Week");
+  });
+
+  it("formats Monthly as This Month", () => {
+    expect(formatAlertType("Monthly")).toBe("This Month");
+  });
+
+  it("handles all AlertType values", () => {
+    const types: AlertType[] = ["Daily", "Weekly", "Monthly"];
+    const results = types.map(formatAlertType);
+    expect(results).toEqual(["Today", "This Week", "This Month"]);
+  });
+});
+
+describe("getAlertMessage", () => {
+  it("generates a message for a Daily alert", () => {
+    const alert: CostAlert = {
+      alert_type: "Daily",
+      threshold: 1.0,
+      current_cost: 1.5,
+    };
+    const message = getAlertMessage(alert);
+    expect(message).toContain("Today");
+    expect(message).toContain("$1.50");
+    expect(message).toContain("$1.00");
+  });
+
+  it("generates a message for a Weekly alert", () => {
+    const alert: CostAlert = {
+      alert_type: "Weekly",
+      threshold: 5.0,
+      current_cost: 6.0,
+    };
+    const message = getAlertMessage(alert);
+    expect(message).toContain("This Week");
+    expect(message).toContain("$6.00");
+    expect(message).toContain("$5.00");
+  });
+
+  it("generates a message for a Monthly alert", () => {
+    const alert: CostAlert = {
+      alert_type: "Monthly",
+      threshold: 20.0,
+      current_cost: 25.0,
+    };
+    const message = getAlertMessage(alert);
+    expect(message).toContain("This Month");
+    expect(message).toContain("$25.00");
+    expect(message).toContain("$20.00");
+  });
+
+  it("includes threshold and current cost in the message", () => {
+    const alert: CostAlert = {
+      alert_type: "Daily",
+      threshold: 0.005,
+      current_cost: 0.007,
+    };
+    const message = getAlertMessage(alert);
+    expect(message).toContain("$0.0070");
+    expect(message).toContain("$0.0050");
+  });
+});
+
+describe("costTrackingStore", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    costTrackingStore.reset();
+  });
+
+  describe("refresh", () => {
+    it("loads cost data from the backend", async () => {
+      setMockInvokeResult("get_today_cost", 1.5);
+      setMockInvokeResult("get_week_cost", 5.25);
+      setMockInvokeResult("get_month_cost", 20.0);
+      setMockInvokeResult("get_cost_alerts", []);
+
+      await costTrackingStore.refresh();
+
+      const state = get(costTrackingStore);
+      expect(state.todayCost).toBe(1.5);
+      expect(state.weekCost).toBe(5.25);
+      expect(state.monthCost).toBe(20.0);
+      expect(state.isLoading).toBe(false);
+    });
+
+    it("triggers notifications for any returned alerts", async () => {
+      const { notificationManager } = await import("$lib/notifications/notificationManager");
+      const alert: CostAlert = { alert_type: "Daily", threshold: 1.0, current_cost: 1.5 };
+      setMockInvokeResult("get_today_cost", 1.5);
+      setMockInvokeResult("get_week_cost", 0);
+      setMockInvokeResult("get_month_cost", 0);
+      setMockInvokeResult("get_cost_alerts", [alert]);
+
+      await costTrackingStore.refresh();
+
+      expect(notificationManager.notifyCostAlert).toHaveBeenCalledWith(
+        expect.stringContaining("Today")
+      );
+    });
+
+    it("returns alerts from refresh", async () => {
+      const alert: CostAlert = { alert_type: "Weekly", threshold: 5.0, current_cost: 6.0 };
+      setMockInvokeResult("get_today_cost", 0);
+      setMockInvokeResult("get_week_cost", 6.0);
+      setMockInvokeResult("get_month_cost", 0);
+      setMockInvokeResult("get_cost_alerts", [alert]);
+
+      const result = await costTrackingStore.refresh();
+
+      expect(result).toEqual([alert]);
+    });
+
+    it("handles refresh errors gracefully and returns empty array", async () => {
+      const errorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      setMockInvokeResult("get_today_cost", new Error("Backend error"));
+
+      const result = await costTrackingStore.refresh();
+
+      expect(result).toEqual([]);
+      expect(errorSpy).toHaveBeenCalledWith("Failed to refresh cost tracking:", expect.any(Error));
+      errorSpy.mockRestore();
+    });
+  });
+
+  describe("getSummary", () => {
+    it("fetches and stores a cost summary", async () => {
+      const mockSummary = {
+        period_days: 7,
+        total_input_tokens: 1000,
+        total_output_tokens: 500,
+        total_cost: 0.05,
+        total_messages: 20,
+        total_sessions: 3,
+        average_daily_cost: 0.007,
+        daily_breakdown: [],
+      };
+      setMockInvokeResult("get_cost_summary", mockSummary);
+
+      const result = await costTrackingStore.getSummary(7);
+
+      expect(result).toEqual(mockSummary);
+      expect(invoke).toHaveBeenCalledWith("get_cost_summary", { days: 7 });
+    });
+
+    it("returns null and logs error on failure", async () => {
+      const errorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      setMockInvokeResult("get_cost_summary", new Error("Summary unavailable"));
+
+      const result = await costTrackingStore.getSummary(30);
+
+      expect(result).toBeNull();
+      expect(errorSpy).toHaveBeenCalledWith("Failed to get cost summary:", expect.any(Error));
+      errorSpy.mockRestore();
+    });
+  });
+
+  describe("setAlertThresholds", () => {
+    it("persists new thresholds to the backend", async () => {
+      const thresholds = { daily: 2.0, weekly: 10.0, monthly: 40.0 };
+
+      await costTrackingStore.setAlertThresholds(thresholds);
+
+      expect(invoke).toHaveBeenCalledWith("set_cost_alert_thresholds", {
+        daily: 2.0,
+        weekly: 10.0,
+        monthly: 40.0,
+      });
+    });
+
+    it("logs an error when the backend call fails", async () => {
+      const errorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      setMockInvokeResult("set_cost_alert_thresholds", new Error("Failed"));
+
+      await costTrackingStore.setAlertThresholds({ daily: 1.0, weekly: null, monthly: null });
+
+      expect(errorSpy).toHaveBeenCalledWith("Failed to set alert thresholds:", expect.any(Error));
+      errorSpy.mockRestore();
+    });
+  });
+
+  describe("exportCsv", () => {
+    it("returns the CSV string from the backend", async () => {
+      setMockInvokeResult("export_cost_csv", "date,cost\n2026-01-01,1.50");
+
+      const result = await costTrackingStore.exportCsv(7);
+
+      expect(result).toBe("date,cost\n2026-01-01,1.50");
+      expect(invoke).toHaveBeenCalledWith("export_cost_csv", { days: 7 });
+    });
+
+    it("returns null and logs error on failure", async () => {
+      const errorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      setMockInvokeResult("export_cost_csv", new Error("Export failed"));
+
+      const result = await costTrackingStore.exportCsv(30);
+
+      expect(result).toBeNull();
+      expect(errorSpy).toHaveBeenCalledWith("Failed to export CSV:", expect.any(Error));
+      errorSpy.mockRestore();
+    });
+  });
+
+  describe("reset", () => {
+    it("resets costs back to zero", async () => {
+      setMockInvokeResult("get_today_cost", 5.0);
+      setMockInvokeResult("get_week_cost", 15.0);
+      setMockInvokeResult("get_month_cost", 50.0);
+      setMockInvokeResult("get_cost_alerts", []);
+      await costTrackingStore.refresh();
+
+      costTrackingStore.reset();
+
+      const state = get(costTrackingStore);
+      expect(state.todayCost).toBe(0);
+      expect(state.weekCost).toBe(0);
+      expect(state.monthCost).toBe(0);
+    });
+  });
+});
+
+describe("formattedCosts", () => {
+  beforeEach(() => {
+    costTrackingStore.reset();
+  });
+
+  it("formats the initial zero costs correctly", () => {
+    const costs = get(formattedCosts);
+    expect(costs.today).toBe("$0.0000");
+    expect(costs.week).toBe("$0.0000");
+    expect(costs.month).toBe("$0.0000");
+  });
+
+  it("reflects updated costs after a refresh", async () => {
+    setMockInvokeResult("get_today_cost", 1.5);
+    setMockInvokeResult("get_week_cost", 5.0);
+    setMockInvokeResult("get_month_cost", 20.0);
+    setMockInvokeResult("get_cost_alerts", []);
+    await costTrackingStore.refresh();
+
+    const costs = get(formattedCosts);
+    expect(costs.today).toBe("$1.50");
+    expect(costs.week).toBe("$5.00");
+    expect(costs.month).toBe("$20.00");
+    expect(costs.todayRaw).toBe(1.5);
+  });
+});

src/lib/stores/debugConsole.test.ts

@@ -0,0 +1,282 @@
+import { describe, it, expect, beforeEach, afterEach } from "vitest";
+import { get } from "svelte/store";
+import { emitMockEvent } from "../../../vitest.setup";
+import { debugConsoleStore, filteredLogs } from "./debugConsole";
+
+describe("debugConsoleStore", () => {
+  beforeEach(() => {
+    debugConsoleStore.clear();
+    debugConsoleStore.close();
+    debugConsoleStore.setFilterLevel("all");
+    debugConsoleStore.setAutoScroll(true);
+  });
+
+  afterEach(() => {
+    debugConsoleStore.restoreConsole();
+    debugConsoleStore.clear();
+  });
+
+  it("initializes with correct default state", () => {
+    const state = get(debugConsoleStore);
+    expect(state.logs).toEqual([]);
+    expect(state.isOpen).toBe(false);
+    expect(state.maxLogs).toBe(1000);
+    expect(state.filterLevel).toBe("all");
+    expect(state.autoScroll).toBe(true);
+  });
+
+  describe("toggle", () => {
+    it("opens when currently closed", () => {
+      debugConsoleStore.toggle();
+      expect(get(debugConsoleStore).isOpen).toBe(true);
+    });
+
+    it("closes when currently open", () => {
+      debugConsoleStore.open();
+      debugConsoleStore.toggle();
+      expect(get(debugConsoleStore).isOpen).toBe(false);
+    });
+  });
+
+  describe("open", () => {
+    it("sets isOpen to true", () => {
+      debugConsoleStore.open();
+      expect(get(debugConsoleStore).isOpen).toBe(true);
+    });
+  });
+
+  describe("close", () => {
+    it("sets isOpen to false", () => {
+      debugConsoleStore.open();
+      debugConsoleStore.close();
+      expect(get(debugConsoleStore).isOpen).toBe(false);
+    });
+  });
+
+  describe("clear", () => {
+    it("removes all log entries", async () => {
+      await debugConsoleStore.setupBackendLogsListener();
+      emitMockEvent("debug:log", { level: "info", message: "test entry" });
+      expect(get(debugConsoleStore).logs.length).toBe(1);
+      debugConsoleStore.clear();
+      expect(get(debugConsoleStore).logs).toEqual([]);
+    });
+  });
+
+  describe("setFilterLevel", () => {
+    it("updates filterLevel to the specified level", () => {
+      debugConsoleStore.setFilterLevel("error");
+      expect(get(debugConsoleStore).filterLevel).toBe("error");
+    });
+
+    it("can reset filterLevel back to all", () => {
+      debugConsoleStore.setFilterLevel("warn");
+      debugConsoleStore.setFilterLevel("all");
+      expect(get(debugConsoleStore).filterLevel).toBe("all");
+    });
+  });
+
+  describe("setAutoScroll", () => {
+    it("disables autoScroll", () => {
+      debugConsoleStore.setAutoScroll(false);
+      expect(get(debugConsoleStore).autoScroll).toBe(false);
+    });
+
+    it("re-enables autoScroll", () => {
+      debugConsoleStore.setAutoScroll(false);
+      debugConsoleStore.setAutoScroll(true);
+      expect(get(debugConsoleStore).autoScroll).toBe(true);
+    });
+  });
+
+  describe("setupConsoleCapture", () => {
+    afterEach(() => {
+      debugConsoleStore.restoreConsole();
+    });
+
+    it("captures console.log calls as info-level frontend logs", () => {
+      debugConsoleStore.setupConsoleCapture();
+      console.log("hello world");
+      const logs = get(debugConsoleStore).logs;
+      const captured = logs.find((l) => l.message === "hello world");
+      expect(captured).toBeDefined();
+      expect(captured?.level).toBe("info");
+      expect(captured?.source).toBe("frontend");
+    });
+
+    it("captures console.info calls as info-level logs", () => {
+      debugConsoleStore.setupConsoleCapture();
+      console.info("info message");
+      const logs = get(debugConsoleStore).logs;
+      const captured = logs.find((l) => l.message === "info message");
+      expect(captured?.level).toBe("info");
+    });
+
+    it("captures console.warn calls as warn-level logs", () => {
+      debugConsoleStore.setupConsoleCapture();
+      console.warn("warning message");
+      const logs = get(debugConsoleStore).logs;
+      const captured = logs.find((l) => l.message === "warning message");
+      expect(captured?.level).toBe("warn");
+    });
+
+    it("captures console.error calls as error-level logs", () => {
+      debugConsoleStore.setupConsoleCapture();
+      console.error("error message");
+      const logs = get(debugConsoleStore).logs;
+      const captured = logs.find((l) => l.message === "error message");
+      expect(captured?.level).toBe("error");
+    });
+
+    it("captures console.debug calls as debug-level logs", () => {
+      debugConsoleStore.setupConsoleCapture();
+      console.debug("debug message");
+      const logs = get(debugConsoleStore).logs;
+      const captured = logs.find((l) => l.message === "debug message");
+      expect(captured?.level).toBe("debug");
+    });
+
+    it("joins multiple console arguments with spaces", () => {
+      debugConsoleStore.setupConsoleCapture();
+      console.log("hello", "world", 42);
+      const logs = get(debugConsoleStore).logs;
+      const captured = logs.find((l) => l.message === "hello world 42");
+      expect(captured).toBeDefined();
+    });
+
+    it("captures unhandled window error events", () => {
+      debugConsoleStore.setupConsoleCapture();
+      const errorEvent = new ErrorEvent("error", {
+        message: "Test unhandled error",
+        filename: "test.js",
+        lineno: 10,
+        colno: 5,
+      });
+      window.dispatchEvent(errorEvent);
+      const logs = get(debugConsoleStore).logs;
+      const captured = logs.find(
+        (l) => l.level === "error" && l.message.includes("[Unhandled Error]")
+      );
+      expect(captured).toBeDefined();
+      expect(captured?.message).toContain("Test unhandled error");
+    });
+
+    it("captures unhandled promise rejection events", () => {
+      debugConsoleStore.setupConsoleCapture();
+      const rejectionEvent = Object.assign(new Event("unhandledrejection"), {
+        reason: "test rejection reason",
+      });
+      window.dispatchEvent(rejectionEvent);
+      const logs = get(debugConsoleStore).logs;
+      const captured = logs.find(
+        (l) => l.level === "error" && l.message.includes("[Unhandled Promise Rejection]")
+      );
+      expect(captured).toBeDefined();
+      expect(captured?.message).toContain("test rejection reason");
+    });
+  });
+
+  describe("restoreConsole", () => {
+    it("stops capturing console output after restore", () => {
+      debugConsoleStore.setupConsoleCapture();
+      debugConsoleStore.restoreConsole();
+      const countBefore = get(debugConsoleStore).logs.length;
+      console.log("this should not be captured");
+      expect(get(debugConsoleStore).logs.length).toBe(countBefore);
+    });
+  });
+
+  describe("setupBackendLogsListener", () => {
+    it("captures backend logs emitted via debug:log event", async () => {
+      await debugConsoleStore.setupBackendLogsListener();
+      emitMockEvent("debug:log", { level: "info", message: "backend message" });
+      const logs = get(debugConsoleStore).logs;
+      expect(logs.length).toBe(1);
+      expect(logs[0].level).toBe("info");
+      expect(logs[0].message).toBe("backend message");
+      expect(logs[0].source).toBe("backend");
+    });
+
+    it("handles different log levels from backend", async () => {
+      await debugConsoleStore.setupBackendLogsListener();
+      emitMockEvent("debug:log", { level: "error", message: "backend error" });
+      const logs = get(debugConsoleStore).logs;
+      expect(logs[0].level).toBe("error");
+    });
+  });
+
+  describe("circular buffer", () => {
+    it("drops oldest log when exceeding 1000-entry limit", async () => {
+      await debugConsoleStore.setupBackendLogsListener();
+      for (let i = 0; i < 1001; i++) {
+        emitMockEvent("debug:log", { level: "info", message: `log ${i}` });
+      }
+      const logs = get(debugConsoleStore).logs;
+      expect(logs.length).toBe(1000);
+      expect(logs[0].message).toBe("log 1");
+      expect(logs[999].message).toBe("log 1000");
+    });
+  });
+});
+
+describe("filteredLogs derived store", () => {
+  beforeEach(async () => {
+    debugConsoleStore.clear();
+    debugConsoleStore.setFilterLevel("all");
+    await debugConsoleStore.setupBackendLogsListener();
+  });
+
+  afterEach(() => {
+    debugConsoleStore.clear();
+  });
+
+  it("returns all logs when filterLevel is all", () => {
+    emitMockEvent("debug:log", { level: "debug", message: "d" });
+    emitMockEvent("debug:log", { level: "info", message: "i" });
+    emitMockEvent("debug:log", { level: "warn", message: "w" });
+    emitMockEvent("debug:log", { level: "error", message: "e" });
+    expect(get(filteredLogs).length).toBe(4);
+  });
+
+  it("returns only error logs when filterLevel is error", () => {
+    emitMockEvent("debug:log", { level: "debug", message: "d" });
+    emitMockEvent("debug:log", { level: "info", message: "i" });
+    emitMockEvent("debug:log", { level: "warn", message: "w" });
+    emitMockEvent("debug:log", { level: "error", message: "e" });
+    debugConsoleStore.setFilterLevel("error");
+    const logs = get(filteredLogs);
+    expect(logs.length).toBe(1);
+    expect(logs[0].level).toBe("error");
+  });
+
+  it("returns warn and error logs when filterLevel is warn", () => {
+    emitMockEvent("debug:log", { level: "debug", message: "d" });
+    emitMockEvent("debug:log", { level: "info", message: "i" });
+    emitMockEvent("debug:log", { level: "warn", message: "w" });
+    emitMockEvent("debug:log", { level: "error", message: "e" });
+    debugConsoleStore.setFilterLevel("warn");
+    const logs = get(filteredLogs);
+    expect(logs.length).toBe(2);
+    expect(logs.every((l) => l.level === "warn" || l.level === "error")).toBe(true);
+  });
+
+  it("excludes debug logs when filterLevel is info", () => {
+    emitMockEvent("debug:log", { level: "debug", message: "d" });
+    emitMockEvent("debug:log", { level: "info", message: "i" });
+    emitMockEvent("debug:log", { level: "warn", message: "w" });
+    emitMockEvent("debug:log", { level: "error", message: "e" });
+    debugConsoleStore.setFilterLevel("info");
+    const logs = get(filteredLogs);
+    expect(logs.length).toBe(3);
+    expect(logs.some((l) => l.level === "debug")).toBe(false);
+  });
+
+  it("returns all log levels when filterLevel is debug", () => {
+    emitMockEvent("debug:log", { level: "debug", message: "d" });
+    emitMockEvent("debug:log", { level: "info", message: "i" });
+    emitMockEvent("debug:log", { level: "warn", message: "w" });
+    emitMockEvent("debug:log", { level: "error", message: "e" });
+    debugConsoleStore.setFilterLevel("debug");
+    expect(get(filteredLogs).length).toBe(4);
+  });
+});

src/lib/stores/drafts.test.ts

@@ -180,6 +180,16 @@ describe("draftsStore", () => {
       const result = draftsStore.formatTimestamp(invalid);
       expect(result).toBe(invalid);
     });
+
+    it("falls back to raw string when toLocaleString throws", () => {
+      const spy = vi.spyOn(Date.prototype, "toLocaleString").mockImplementation(() => {
+        throw new Error("Locale not supported");
+      });
+      const ts = "2026-01-15T14:30:00.000Z";
+      const result = draftsStore.formatTimestamp(ts);
+      expect(result).toBe(ts);
+      spy.mockRestore();
+    });
   });
 });
 

src/lib/stores/editor.test.ts

@@ -0,0 +1,639 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { get } from "svelte/store";
+import { editorStore } from "$lib/stores/editor";
+import { setMockInvokeResult } from "../../../vitest.setup";
+
+const FILE_CONTENT = "// test file content";
+
+// Reset tabs between tests
+afterEach(async () => {
+  const tabs = get(editorStore.tabs);
+  for (const tab of tabs) {
+    editorStore.closeTab(tab.id);
+  }
+  editorStore.hideEditor();
+});
+
+describe("editorStore - openFile (tests getLanguageFromPath)", () => {
+  const testCases: [string, string][] = [
+    ["file.ts", "typescript"],
+    ["file.tsx", "typescript"],
+    ["file.js", "javascript"],
+    ["file.jsx", "javascript"],
+    ["file.py", "python"],
+    ["file.rs", "rust"],
+    ["file.go", "go"],
+    ["file.java", "java"],
+    ["file.c", "c"],
+    ["file.cpp", "cpp"],
+    ["file.h", "c"],
+    ["file.hpp", "cpp"],
+    ["file.cs", "csharp"],
+    ["file.rb", "ruby"],
+    ["file.php", "php"],
+    ["file.swift", "swift"],
+    ["file.kt", "kotlin"],
+    ["file.scala", "scala"],
+    ["file.html", "html"],
+    ["file.htm", "html"],
+    ["file.css", "css"],
+    ["file.scss", "scss"],
+    ["file.sass", "sass"],
+    ["file.less", "less"],
+    ["file.json", "json"],
+    ["file.xml", "xml"],
+    ["file.yaml", "yaml"],
+    ["file.yml", "yaml"],
+    ["file.toml", "toml"],
+    ["file.md", "markdown"],
+    ["file.markdown", "markdown"],
+    ["file.sql", "sql"],
+    ["file.sh", "shell"],
+    ["file.bash", "shell"],
+    ["file.zsh", "shell"],
+    ["file.ps1", "powershell"],
+    ["file.svelte", "svelte"],
+    ["file.vue", "vue"],
+    ["file.graphql", "graphql"],
+    ["file.gql", "graphql"],
+    ["file.lua", "lua"],
+    ["file.r", "r"],
+    ["file.dart", "dart"],
+    ["file.elm", "elm"],
+    ["file.ex", "elixir"],
+    ["file.exs", "elixir"],
+    ["file.erl", "erlang"],
+    ["file.hs", "haskell"],
+    ["file.clj", "clojure"],
+    ["file.lisp", "lisp"],
+    ["file.ml", "ocaml"],
+    ["file.fs", "fsharp"],
+    ["file.zig", "zig"],
+    ["file.nim", "nim"],
+    ["file.v", "v"],
+    ["file.wasm", "wasm"],
+    ["file.wat", "wasm"],
+    ["dockerfile", "plaintext"],
+    ["file.unknown", "plaintext"],
+    ["file", "plaintext"],
+  ];
+
+  it.each(testCases)("maps %s to language %s", async (filename, expectedLanguage) => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile(`/path/to/${filename}`);
+    const activeTab = get(editorStore.activeTab);
+    expect(activeTab?.language).toBe(expectedLanguage);
+    if (activeTab) editorStore.closeTab(activeTab.id);
+  });
+
+  it("opens a new tab and makes it active", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/file.ts");
+    const tabs = get(editorStore.tabs);
+    const activeTab = get(editorStore.activeTab);
+    expect(tabs).toHaveLength(1);
+    expect(activeTab?.fileName).toBe("file.ts");
+    expect(activeTab?.content).toBe(FILE_CONTENT);
+    expect(activeTab?.isDirty).toBe(false);
+  });
+
+  it("switches to existing tab instead of opening a duplicate", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/file.ts");
+    const firstTabId = get(editorStore.activeTabId);
+
+    // Open another file to change active tab
+    await editorStore.openFile("/path/to/other.ts");
+    const secondTabId = get(editorStore.activeTabId);
+    expect(secondTabId).not.toBe(firstTabId);
+
+    // Re-open first file — should switch to existing tab
+    await editorStore.openFile("/path/to/file.ts");
+    expect(get(editorStore.activeTabId)).toBe(firstTabId);
+    expect(get(editorStore.tabs)).toHaveLength(2);
+  });
+
+  it("handles open file errors gracefully", async () => {
+    const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("read_file_content", new Error("File not found"));
+    await editorStore.openFile("/path/to/missing.ts");
+    expect(get(editorStore.tabs)).toHaveLength(0);
+    expect(get(editorStore.saveError)).toContain("Failed to open file");
+    consoleErrorSpy.mockRestore();
+  });
+
+  it("extracts filename from path correctly", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/deep/nested/path/component.svelte");
+    expect(get(editorStore.activeTab)?.fileName).toBe("component.svelte");
+  });
+});
+
+describe("editorStore - saveFile", () => {
+  beforeEach(async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/file.ts");
+    // Make it dirty first
+    editorStore.updateTabContent(get(editorStore.activeTabId)!, "modified content");
+  });
+
+  it("saves the active tab successfully", async () => {
+    setMockInvokeResult("write_file_content", undefined);
+    await editorStore.saveFile();
+    expect(get(editorStore.activeTab)?.isDirty).toBe(false);
+    expect(get(editorStore.activeTab)?.originalContent).toBe("modified content");
+  });
+
+  it("saves a specific tab by ID", async () => {
+    setMockInvokeResult("write_file_content", undefined);
+    const tabId = get(editorStore.activeTabId)!;
+    await editorStore.saveFile(tabId);
+    expect(get(editorStore.activeTab)?.isDirty).toBe(false);
+  });
+
+  it("does nothing when no tab ID matches", async () => {
+    await editorStore.saveFile("non-existent-tab");
+    // No error = pass
+  });
+});
+
+describe("editorStore - saveFile error", () => {
+  it("sets saveError when write fails", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/file-err.ts");
+    editorStore.updateTabContent(get(editorStore.activeTabId)!, "modified content");
+    const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("write_file_content", new Error("Permission denied"));
+    await editorStore.saveFile().catch(() => {});
+    expect(get(editorStore.saveError)).toContain("Failed to save file");
+    consoleErrorSpy.mockRestore();
+  });
+});
+
+describe("editorStore - updateTabContent", () => {
+  beforeEach(async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/file.ts");
+  });
+
+  it("updates content and marks tab as dirty", () => {
+    const tabId = get(editorStore.activeTabId)!;
+    editorStore.updateTabContent(tabId, "new content");
+    const tab = get(editorStore.activeTab);
+    expect(tab?.content).toBe("new content");
+    expect(tab?.isDirty).toBe(true);
+  });
+
+  it("marks tab as clean when content matches original", () => {
+    const tabId = get(editorStore.activeTabId)!;
+    editorStore.updateTabContent(tabId, "modified");
+    expect(get(editorStore.activeTab)?.isDirty).toBe(true);
+    editorStore.updateTabContent(tabId, FILE_CONTENT);
+    expect(get(editorStore.activeTab)?.isDirty).toBe(false);
+  });
+
+  it("hasDirtyTabs is true when any tab is dirty", () => {
+    const tabId = get(editorStore.activeTabId)!;
+    expect(get(editorStore.hasDirtyTabs)).toBe(false);
+    editorStore.updateTabContent(tabId, "dirty content");
+    expect(get(editorStore.hasDirtyTabs)).toBe(true);
+  });
+});
+
+describe("editorStore - closeTab", () => {
+  beforeEach(async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/file1.ts");
+    await editorStore.openFile("/path/to/file2.ts");
+  });
+
+  it("removes the specified tab", () => {
+    const tabs = get(editorStore.tabs);
+    editorStore.closeTab(tabs[0].id);
+    expect(get(editorStore.tabs)).toHaveLength(1);
+    expect(get(editorStore.tabs)[0].filePath).toBe("/path/to/file2.ts");
+  });
+
+  it("sets active tab to remaining tab when active tab is closed", () => {
+    const activeTabId = get(editorStore.activeTabId)!;
+    editorStore.closeTab(activeTabId);
+    expect(get(editorStore.activeTabId)).not.toBe(activeTabId);
+    expect(get(editorStore.tabs)).toHaveLength(1);
+  });
+});
+
+describe("editorStore - setActiveTab", () => {
+  beforeEach(async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/file1.ts");
+    await editorStore.openFile("/path/to/file2.ts");
+  });
+
+  it("sets the active tab to the specified ID", () => {
+    const tabs = get(editorStore.tabs);
+    editorStore.setActiveTab(tabs[0].id);
+    expect(get(editorStore.activeTabId)).toBe(tabs[0].id);
+  });
+});
+
+describe("editorStore - visibility controls", () => {
+  it("showEditor sets isEditorVisible to true", () => {
+    expect(get(editorStore.isEditorVisible)).toBe(false);
+    editorStore.showEditor();
+    expect(get(editorStore.isEditorVisible)).toBe(true);
+  });
+
+  it("hideEditor sets isEditorVisible to false", () => {
+    editorStore.showEditor();
+    editorStore.hideEditor();
+    expect(get(editorStore.isEditorVisible)).toBe(false);
+  });
+
+  it("toggleEditor toggles isEditorVisible", () => {
+    expect(get(editorStore.isEditorVisible)).toBe(false);
+    editorStore.toggleEditor();
+    expect(get(editorStore.isEditorVisible)).toBe(true);
+    editorStore.toggleEditor();
+    expect(get(editorStore.isEditorVisible)).toBe(false);
+  });
+});
+
+describe("editorStore - toggleFileBrowser", () => {
+  it("toggles the file browser visibility", () => {
+    const initial = get(editorStore.isFileBrowserOpen);
+    editorStore.toggleFileBrowser();
+    expect(get(editorStore.isFileBrowserOpen)).toBe(!initial);
+    editorStore.toggleFileBrowser();
+    expect(get(editorStore.isFileBrowserOpen)).toBe(initial);
+  });
+});
+
+describe("editorStore - file system operations", () => {
+  it("createFile invokes backend and refreshes directory", async () => {
+    setMockInvokeResult("create_file", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.createFile("/path/to", "new-file.ts");
+    // No error = success
+  });
+
+  it("createFile handles errors gracefully", async () => {
+    const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("create_file", new Error("Permission denied"));
+    await editorStore.createFile("/path/to", "new-file.ts");
+    expect(consoleErrorSpy).toHaveBeenCalledWith("Failed to create file:", expect.any(Error));
+    consoleErrorSpy.mockRestore();
+  });
+
+  it("createDirectory invokes backend and refreshes", async () => {
+    setMockInvokeResult("create_directory", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.createDirectory("/path/to", "new-dir");
+  });
+
+  it("createDirectory handles errors gracefully", async () => {
+    const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("create_directory", new Error("Failed"));
+    await editorStore.createDirectory("/path/to", "new-dir");
+    expect(consoleErrorSpy).toHaveBeenCalledWith("Failed to create directory:", expect.any(Error));
+    consoleErrorSpy.mockRestore();
+  });
+
+  it("deleteFile invokes backend and refreshes", async () => {
+    setMockInvokeResult("delete_file", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.deleteFile("/path/to/file.ts");
+  });
+
+  it("deleteFile handles errors gracefully", async () => {
+    const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("delete_file", new Error("Failed"));
+    await editorStore.deleteFile("/path/to/file.ts");
+    expect(consoleErrorSpy).toHaveBeenCalledWith("Failed to delete file:", expect.any(Error));
+    consoleErrorSpy.mockRestore();
+  });
+
+  it("deleteDirectory invokes backend and refreshes", async () => {
+    setMockInvokeResult("delete_directory", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.deleteDirectory("/path/to/dir");
+  });
+
+  it("deleteDirectory handles errors gracefully", async () => {
+    const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("delete_directory", new Error("Failed"));
+    await editorStore.deleteDirectory("/path/to/dir");
+    expect(consoleErrorSpy).toHaveBeenCalledWith("Failed to delete directory:", expect.any(Error));
+    consoleErrorSpy.mockRestore();
+  });
+
+  it("renamePath invokes backend and refreshes", async () => {
+    setMockInvokeResult("rename_path", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.renamePath("/path/to/old-name.ts", "new-name.ts");
+  });
+
+  it("renamePath handles errors gracefully", async () => {
+    const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("rename_path", new Error("Failed"));
+    await editorStore.renamePath("/path/to/old-name.ts", "new-name.ts");
+    expect(consoleErrorSpy).toHaveBeenCalledWith("Failed to rename:", expect.any(Error));
+    consoleErrorSpy.mockRestore();
+  });
+});
+
+describe("editorStore - initializeFileTree", () => {
+  it("loads directory entries and updates file tree", async () => {
+    const entries = [
+      { path: "/path/file.ts", name: "file.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", entries);
+    await editorStore.initializeFileTree("/path");
+    expect(get(editorStore.fileTree)).toEqual(entries);
+    expect(get(editorStore.currentDirectory)).toBe("/path");
+  });
+
+  it("handles errors gracefully", async () => {
+    const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("list_directory", new Error("Failed"));
+    await editorStore.initializeFileTree("/path");
+    expect(get(editorStore.isLoadingTree)).toBe(false);
+    consoleErrorSpy.mockRestore();
+  });
+});
+
+describe("editorStore - toggleDirectory", () => {
+  beforeEach(async () => {
+    const entries = [
+      {
+        path: "/path/dir",
+        name: "dir",
+        isDirectory: true,
+        isExpanded: false,
+        children: undefined,
+      },
+    ];
+    setMockInvokeResult("list_directory", entries);
+    await editorStore.initializeFileTree("/path");
+  });
+
+  it("does nothing when entry is not a directory", async () => {
+    const nonDirEntry = {
+      path: "/path/file.ts",
+      name: "file.ts",
+      isDirectory: false,
+    };
+    const treeBefore = get(editorStore.fileTree);
+    await editorStore.toggleDirectory(nonDirEntry);
+    expect(get(editorStore.fileTree)).toEqual(treeBefore);
+  });
+
+  it("expands a collapsed directory and loads children asynchronously", async () => {
+    const children = [
+      { path: "/path/dir/child.ts", name: "child.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", children);
+
+    const dirEntry = get(editorStore.fileTree)[0];
+    await editorStore.toggleDirectory(dirEntry);
+
+    const updatedEntry = get(editorStore.fileTree)[0];
+    expect(updatedEntry.isExpanded).toBe(true);
+    expect(updatedEntry.children).toEqual(children);
+    expect(updatedEntry.isLoading).toBe(false);
+  });
+
+  it("collapses an expanded directory", async () => {
+    const children = [
+      { path: "/path/dir/child.ts", name: "child.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", children);
+
+    // Expand first
+    const dirEntry = get(editorStore.fileTree)[0];
+    await editorStore.toggleDirectory(dirEntry);
+    expect(get(editorStore.fileTree)[0].isExpanded).toBe(true);
+
+    // Now collapse
+    const expandedEntry = get(editorStore.fileTree)[0];
+    await editorStore.toggleDirectory(expandedEntry);
+    expect(get(editorStore.fileTree)[0].isExpanded).toBe(false);
+  });
+
+  it("expands a directory that already has children without reloading", async () => {
+    // Re-init with a directory that already has children
+    const entries = [
+      {
+        path: "/path/dir",
+        name: "dir",
+        isDirectory: true,
+        isExpanded: false,
+        children: [
+          {
+            path: "/path/dir/child.ts",
+            name: "child.ts",
+            isDirectory: false,
+            children: undefined,
+          },
+        ],
+      },
+    ];
+    setMockInvokeResult("list_directory", entries);
+    await editorStore.initializeFileTree("/path");
+
+    // Toggle should expand without loading (children already present)
+    const dirEntry = get(editorStore.fileTree)[0];
+    await editorStore.toggleDirectory(dirEntry);
+
+    const updatedEntry = get(editorStore.fileTree)[0];
+    expect(updatedEntry.isExpanded).toBe(true);
+    expect(updatedEntry.children).toHaveLength(1);
+  });
+
+  it("handles tree with multiple entries when toggling — exercises non-matching leaf fallback", async () => {
+    // Tree has dir + a sibling file; toggling dir exercises the `return e` branch for the file
+    const entries = [
+      {
+        path: "/path/dir",
+        name: "dir",
+        isDirectory: true,
+        isExpanded: false,
+        children: undefined,
+      },
+      { path: "/path/file.ts", name: "file.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", entries);
+    await editorStore.initializeFileTree("/path");
+
+    const children: never[] = [];
+    setMockInvokeResult("list_directory", children);
+    const dirEntry = get(editorStore.fileTree)[0];
+    await editorStore.toggleDirectory(dirEntry);
+
+    // The sibling file should remain unchanged
+    expect(get(editorStore.fileTree)[1].path).toBe("/path/file.ts");
+    expect(get(editorStore.fileTree)[0].isExpanded).toBe(true);
+  });
+
+  it("handles nested directory toggle — exercises recursive updateTree branches", async () => {
+    // Tree: outer_dir → [inner_dir (no children), sibling_file]
+    // Toggling inner_dir covers the recursive path through outer's children
+    const entries = [
+      {
+        path: "/path/outer",
+        name: "outer",
+        isDirectory: true,
+        isExpanded: true,
+        children: [
+          {
+            path: "/path/outer/inner",
+            name: "inner",
+            isDirectory: true,
+            isExpanded: false,
+            children: undefined,
+          },
+          {
+            path: "/path/outer/sibling.ts",
+            name: "sibling.ts",
+            isDirectory: false,
+            children: undefined,
+          },
+        ],
+      },
+    ];
+    setMockInvokeResult("list_directory", entries);
+    await editorStore.initializeFileTree("/path");
+
+    const innerChildren = [
+      {
+        path: "/path/outer/inner/deep.ts",
+        name: "deep.ts",
+        isDirectory: false,
+        children: undefined,
+      },
+    ];
+    setMockInvokeResult("list_directory", innerChildren);
+
+    const innerEntry = get(editorStore.fileTree)[0].children![0];
+    await editorStore.toggleDirectory(innerEntry);
+
+    const outer = get(editorStore.fileTree)[0];
+    expect(outer.children![0].isExpanded).toBe(true);
+    expect(outer.children![0].children).toEqual(innerChildren);
+  });
+});
+
+describe("editorStore - deleteFile closes open tab", () => {
+  it("closes the tab when the deleted file is open", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/file.ts");
+    expect(get(editorStore.tabs)).toHaveLength(1);
+
+    setMockInvokeResult("delete_file", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.deleteFile("/path/to/file.ts");
+    expect(get(editorStore.tabs)).toHaveLength(0);
+  });
+});
+
+describe("editorStore - deleteDirectory closes open tabs", () => {
+  it("closes all tabs inside the deleted directory", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/dir/file1.ts");
+    await editorStore.openFile("/path/to/dir/nested/file2.ts");
+    await editorStore.openFile("/path/to/other.ts");
+    expect(get(editorStore.tabs)).toHaveLength(3);
+
+    setMockInvokeResult("delete_directory", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.deleteDirectory("/path/to/dir");
+
+    const remainingTabs = get(editorStore.tabs);
+    expect(remainingTabs).toHaveLength(1);
+    expect(remainingTabs[0].filePath).toBe("/path/to/other.ts");
+  });
+});
+
+describe("editorStore - renamePath updates open tabs", () => {
+  it("updates filePath and fileName when the renamed file is open in a tab", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/old-name.ts");
+
+    setMockInvokeResult("rename_path", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.renamePath("/path/to/old-name.ts", "new-name.ts");
+
+    const tab = get(editorStore.activeTab);
+    expect(tab?.filePath).toBe("/path/to/new-name.ts");
+    expect(tab?.fileName).toBe("new-name.ts");
+  });
+
+  it("updates filePaths for tabs inside a renamed directory", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/old-dir/file.ts");
+
+    setMockInvokeResult("rename_path", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.renamePath("/path/to/old-dir", "new-dir");
+
+    const tab = get(editorStore.activeTab);
+    expect(tab?.filePath).toBe("/path/to/new-dir/file.ts");
+  });
+
+  it("leaves unrelated tabs unchanged when renaming — exercises return-t fallback", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/unrelated.ts");
+    await editorStore.openFile("/path/to/old-name.ts");
+
+    setMockInvokeResult("rename_path", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.renamePath("/path/to/old-name.ts", "new-name.ts");
+
+    const tabs = get(editorStore.tabs);
+    const unrelated = tabs.find((t) => t.filePath === "/path/to/unrelated.ts");
+    expect(unrelated).toBeDefined();
+    expect(unrelated?.fileName).toBe("unrelated.ts");
+  });
+});
+
+describe("editorStore - refreshDirectory", () => {
+  it("reloads the entire tree when refreshing the root directory", async () => {
+    const initialEntries = [
+      { path: "/root/file.ts", name: "file.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", initialEntries);
+    await editorStore.initializeFileTree("/root");
+    expect(get(editorStore.fileTree)).toHaveLength(1);
+
+    const updatedEntries = [
+      { path: "/root/file.ts", name: "file.ts", isDirectory: false, children: undefined },
+      { path: "/root/new.ts", name: "new.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", updatedEntries);
+    await editorStore.refreshDirectory("/root");
+    expect(get(editorStore.fileTree)).toHaveLength(2);
+  });
+
+  it("updates a subdirectory entry in the tree", async () => {
+    const initialEntries = [
+      {
+        path: "/root/subdir",
+        name: "subdir",
+        isDirectory: true,
+        isExpanded: true,
+        children: [],
+      },
+    ];
+    setMockInvokeResult("list_directory", initialEntries);
+    await editorStore.initializeFileTree("/root");
+
+    const subChildren = [
+      { path: "/root/subdir/file.ts", name: "file.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", subChildren);
+    await editorStore.refreshDirectory("/root/subdir");
+
+    const tree = get(editorStore.fileTree);
+    expect(tree[0].children).toEqual(subChildren);
+    expect(tree[0].isExpanded).toBe(true);
+  });
+});

src/lib/stores/historyRestore.test.ts

@@ -0,0 +1,72 @@
+import { describe, it, expect, beforeEach } from "vitest";
+import {
+  setShouldRestoreHistory,
+  setSavedHistory,
+  getShouldRestoreHistory,
+  getSavedHistory,
+  clearHistoryRestore,
+} from "./historyRestore";
+
+describe("historyRestore module", () => {
+  beforeEach(() => {
+    clearHistoryRestore();
+  });
+
+  describe("initial state", () => {
+    it("shouldRestoreHistory is false by default", () => {
+      expect(getShouldRestoreHistory()).toBe(false);
+    });
+
+    it("savedHistory is null by default", () => {
+      expect(getSavedHistory()).toBeNull();
+    });
+  });
+
+  describe("setShouldRestoreHistory", () => {
+    it("sets shouldRestoreHistory to true", () => {
+      setShouldRestoreHistory(true);
+      expect(getShouldRestoreHistory()).toBe(true);
+    });
+
+    it("sets shouldRestoreHistory to false", () => {
+      setShouldRestoreHistory(true);
+      setShouldRestoreHistory(false);
+      expect(getShouldRestoreHistory()).toBe(false);
+    });
+  });
+
+  describe("setSavedHistory", () => {
+    it("sets the saved history string", () => {
+      setSavedHistory("some history content");
+      expect(getSavedHistory()).toBe("some history content");
+    });
+
+    it("sets the saved history to null", () => {
+      setSavedHistory("some history content");
+      setSavedHistory(null);
+      expect(getSavedHistory()).toBeNull();
+    });
+  });
+
+  describe("clearHistoryRestore", () => {
+    it("resets shouldRestoreHistory to false", () => {
+      setShouldRestoreHistory(true);
+      clearHistoryRestore();
+      expect(getShouldRestoreHistory()).toBe(false);
+    });
+
+    it("resets savedHistory to null", () => {
+      setSavedHistory("some content");
+      clearHistoryRestore();
+      expect(getSavedHistory()).toBeNull();
+    });
+
+    it("clears both values at once", () => {
+      setShouldRestoreHistory(true);
+      setSavedHistory("history");
+      clearHistoryRestore();
+      expect(getShouldRestoreHistory()).toBe(false);
+      expect(getSavedHistory()).toBeNull();
+    });
+  });
+});

src/lib/stores/messageMode.test.ts

@@ -0,0 +1,56 @@
+import { describe, it, expect, beforeEach } from "vitest";
+import { get } from "svelte/store";
+import { messageMode, getCurrentMode } from "./messageMode";
+
+describe("messageMode store", () => {
+  beforeEach(() => {
+    messageMode.reset();
+  });
+
+  describe("initial state", () => {
+    it("defaults to chat mode", () => {
+      expect(get(messageMode)).toBe("chat");
+    });
+  });
+
+  describe("set", () => {
+    it("sets the mode to the given value", () => {
+      messageMode.set("plan");
+      expect(get(messageMode)).toBe("plan");
+    });
+
+    it("can set any arbitrary mode string", () => {
+      messageMode.set("auto");
+      expect(get(messageMode)).toBe("auto");
+    });
+  });
+
+  describe("reset", () => {
+    it("resets mode back to chat", () => {
+      messageMode.set("plan");
+      messageMode.reset();
+      expect(get(messageMode)).toBe("chat");
+    });
+  });
+});
+
+describe("getCurrentMode", () => {
+  beforeEach(() => {
+    messageMode.reset();
+  });
+
+  it("returns chat when in default state", () => {
+    expect(getCurrentMode()).toBe("chat");
+  });
+
+  it("returns the currently set mode", () => {
+    messageMode.set("plan");
+    expect(getCurrentMode()).toBe("plan");
+  });
+
+  it("returns chat after a reset", () => {
+    messageMode.set("auto");
+    messageMode.reset();
+    expect(getCurrentMode()).toBe("chat");
+  });
+});

src/lib/stores/notifications.test.ts

@@ -0,0 +1,104 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { writable } from "svelte/store";
+
+const mockSetEnabled = vi.fn();
+const mockSetGlobalVolume = vi.fn();
+
+vi.mock("$lib/notifications", () => ({
+  soundPlayer: {
+    setEnabled: mockSetEnabled,
+    setGlobalVolume: mockSetGlobalVolume,
+  },
+}));
+
+// We need to control the config store's emitted values
+const configWritable = writable({
+  notifications_enabled: true,
+  notification_volume: 0.7,
+});
+
+vi.mock("./config", () => ({
+  configStore: {
+    config: { subscribe: configWritable.subscribe },
+  },
+}));
+
+describe("notifications sync store", () => {
+  beforeEach(async () => {
+    vi.resetModules();
+    mockSetEnabled.mockReset();
+    mockSetGlobalVolume.mockReset();
+    configWritable.set({ notifications_enabled: true, notification_volume: 0.7 });
+  });
+
+  afterEach(async () => {
+    // Re-import to clean up any lingering subscriptions
+    const { cleanupNotificationSync } = await import("./notifications");
+    cleanupNotificationSync();
+  });
+
+  describe("initNotificationSync", () => {
+    it("syncs soundPlayer enabled state from config on init", async () => {
+      const { initNotificationSync } = await import("./notifications");
+      initNotificationSync();
+      expect(mockSetEnabled).toHaveBeenCalledWith(true);
+    });
+
+    it("syncs soundPlayer volume from config on init", async () => {
+      const { initNotificationSync } = await import("./notifications");
+      initNotificationSync();
+      expect(mockSetGlobalVolume).toHaveBeenCalledWith(0.7);
+    });
+
+    it("updates soundPlayer when config changes", async () => {
+      const { initNotificationSync } = await import("./notifications");
+      initNotificationSync();
+
+      mockSetEnabled.mockReset();
+      mockSetGlobalVolume.mockReset();
+
+      configWritable.set({ notifications_enabled: false, notification_volume: 0.3 });
+
+      expect(mockSetEnabled).toHaveBeenCalledWith(false);
+      expect(mockSetGlobalVolume).toHaveBeenCalledWith(0.3);
+    });
+
+    it("does not register a duplicate subscription when called twice", async () => {
+      const { initNotificationSync } = await import("./notifications");
+      initNotificationSync();
+      initNotificationSync();
+
+      // Both calls should only produce one subscription (one initial sync)
+      expect(mockSetEnabled).toHaveBeenCalledTimes(1);
+    });
+  });
+
+  describe("cleanupNotificationSync", () => {
+    it("stops reacting to config changes after cleanup", async () => {
+      const { initNotificationSync, cleanupNotificationSync } = await import("./notifications");
+      initNotificationSync();
+      cleanupNotificationSync();
+
+      mockSetEnabled.mockReset();
+      configWritable.set({ notifications_enabled: false, notification_volume: 0.5 });
+
+      expect(mockSetEnabled).not.toHaveBeenCalled();
+    });
+
+    it("is safe to call when not initialised", async () => {
+      const { cleanupNotificationSync } = await import("./notifications");
+      expect(() => cleanupNotificationSync()).not.toThrow();
+    });
+
+    it("allows re-initialisation after cleanup", async () => {
+      const { initNotificationSync, cleanupNotificationSync } = await import("./notifications");
+      initNotificationSync();
+      cleanupNotificationSync();
+
+      mockSetEnabled.mockReset();
+      initNotificationSync();
+
+      expect(mockSetEnabled).toHaveBeenCalledTimes(1);
+    });
+  });
+});

src/lib/stores/search.test.ts

@@ -0,0 +1,187 @@
+import { describe, it, expect, beforeEach } from "vitest";
+import { get } from "svelte/store";
+import { searchState, isSearchActive, searchQuery } from "./search";
+
+describe("searchState store", () => {
+  beforeEach(() => {
+    searchState.clear();
+  });
+
+  describe("initial state", () => {
+    it("starts with empty query", () => {
+      const state = get(searchState);
+      expect(state.query).toBe("");
+    });
+
+    it("starts inactive", () => {
+      const state = get(searchState);
+      expect(state.isActive).toBe(false);
+    });
+
+    it("starts with zero match count", () => {
+      const state = get(searchState);
+      expect(state.matchCount).toBe(0);
+    });
+
+    it("starts with zero current match index", () => {
+      const state = get(searchState);
+      expect(state.currentMatchIndex).toBe(0);
+    });
+  });
+
+  describe("setQuery", () => {
+    it("sets the query string", () => {
+      searchState.setQuery("hello");
+      expect(get(searchState).query).toBe("hello");
+    });
+
+    it("activates the store when query is non-empty", () => {
+      searchState.setQuery("hello");
+      expect(get(searchState).isActive).toBe(true);
+    });
+
+    it("deactivates the store when query is empty", () => {
+      searchState.setQuery("hello");
+      searchState.setQuery("");
+      expect(get(searchState).isActive).toBe(false);
+    });
+
+    it("resets currentMatchIndex to 0 on each query change", () => {
+      searchState.setQuery("hello");
+      searchState.setMatchCount(5);
+      searchState.nextMatch();
+      searchState.nextMatch();
+      searchState.setQuery("world");
+      expect(get(searchState).currentMatchIndex).toBe(0);
+    });
+  });
+
+  describe("setMatchCount", () => {
+    it("updates the match count", () => {
+      searchState.setMatchCount(7);
+      expect(get(searchState).matchCount).toBe(7);
+    });
+
+    it("does not reset currentMatchIndex", () => {
+      searchState.setQuery("test");
+      searchState.setMatchCount(5);
+      searchState.nextMatch();
+      searchState.setMatchCount(10);
+      expect(get(searchState).currentMatchIndex).toBe(1);
+    });
+  });
+
+  describe("nextMatch", () => {
+    it("advances to the next match index", () => {
+      searchState.setMatchCount(5);
+      searchState.nextMatch();
+      expect(get(searchState).currentMatchIndex).toBe(1);
+    });
+
+    it("wraps around to 0 after the last match", () => {
+      searchState.setMatchCount(3);
+      searchState.nextMatch();
+      searchState.nextMatch();
+      searchState.nextMatch();
+      expect(get(searchState).currentMatchIndex).toBe(0);
+    });
+
+    it("stays at 0 when match count is 0", () => {
+      searchState.setMatchCount(0);
+      searchState.nextMatch();
+      expect(get(searchState).currentMatchIndex).toBe(0);
+    });
+  });
+
+  describe("previousMatch", () => {
+    it("goes to the previous match index", () => {
+      searchState.setMatchCount(5);
+      searchState.nextMatch();
+      searchState.nextMatch();
+      searchState.previousMatch();
+      expect(get(searchState).currentMatchIndex).toBe(1);
+    });
+
+    it("wraps around to last match when at index 0", () => {
+      searchState.setMatchCount(5);
+      searchState.previousMatch();
+      expect(get(searchState).currentMatchIndex).toBe(4);
+    });
+
+    it("stays at 0 when match count is 0", () => {
+      searchState.setMatchCount(0);
+      searchState.previousMatch();
+      expect(get(searchState).currentMatchIndex).toBe(0);
+    });
+  });
+
+  describe("clear", () => {
+    it("resets query to empty string", () => {
+      searchState.setQuery("hello");
+      searchState.clear();
+      expect(get(searchState).query).toBe("");
+    });
+
+    it("resets isActive to false", () => {
+      searchState.setQuery("hello");
+      searchState.clear();
+      expect(get(searchState).isActive).toBe(false);
+    });
+
+    it("resets matchCount to 0", () => {
+      searchState.setMatchCount(10);
+      searchState.clear();
+      expect(get(searchState).matchCount).toBe(0);
+    });
+
+    it("resets currentMatchIndex to 0", () => {
+      searchState.setMatchCount(5);
+      searchState.nextMatch();
+      searchState.nextMatch();
+      searchState.clear();
+      expect(get(searchState).currentMatchIndex).toBe(0);
+    });
+  });
+});
+
+describe("isSearchActive derived store", () => {
+  beforeEach(() => {
+    searchState.clear();
+  });
+
+  it("is false initially", () => {
+    expect(get(isSearchActive)).toBe(false);
+  });
+
+  it("is true when query is set", () => {
+    searchState.setQuery("test");
+    expect(get(isSearchActive)).toBe(true);
+  });
+
+  it("is false after clearing", () => {
+    searchState.setQuery("test");
+    searchState.clear();
+    expect(get(isSearchActive)).toBe(false);
+  });
+});
+
+describe("searchQuery derived store", () => {
+  beforeEach(() => {
+    searchState.clear();
+  });
+
+  it("is empty string initially", () => {
+    expect(get(searchQuery)).toBe("");
+  });
+
+  it("reflects the current query", () => {
+    searchState.setQuery("my search");
+    expect(get(searchQuery)).toBe("my search");
+  });
+
+  it("is empty after clearing", () => {
+    searchState.setQuery("test");
+    searchState.clear();
+    expect(get(searchQuery)).toBe("");
+  });
+});

src/lib/stores/sessions.test.ts

@@ -0,0 +1,569 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { get } from "svelte/store";
+import { sessionsStore } from "$lib/stores/sessions";
+import { setMockInvokeResult } from "../../../vitest.setup";
+import type { SavedSession } from "$lib/stores/sessions";
+
+vi.mock("@tauri-apps/plugin-dialog", () => ({
+  save: vi.fn(),
+  open: vi.fn(),
+}));
+
+vi.mock("@tauri-apps/plugin-fs", () => ({
+  writeTextFile: vi.fn().mockResolvedValue(undefined),
+  readTextFile: vi.fn(),
+}));
+
+vi.mock("@tauri-apps/plugin-opener", () => ({
+  openPath: vi.fn().mockResolvedValue(undefined),
+}));
+
+const makeSavedSession = (overrides: Partial<SavedSession> = {}): SavedSession => ({
+  id: "session-1",
+  name: "Test Session",
+  created_at: "2026-03-03T10:00:00.000Z",
+  last_activity_at: "2026-03-03T11:00:00.000Z",
+  working_directory: "/home/naomi/code",
+  message_count: 2,
+  preview: "Hello world",
+  messages: [
+    { id: "msg-1", type: "user", content: "Hello world", timestamp: "2026-03-03T10:00:00.000Z" },
+    { id: "msg-2", type: "assistant", content: "Hi there!", timestamp: "2026-03-03T10:01:00.000Z" },
+  ],
+  ...overrides,
+});
+
+const makeConversation = () => ({
+  id: "conv-1",
+  name: "Test Conversation",
+  workingDirectory: "/home/naomi/code",
+  createdAt: new Date("2026-03-03T10:00:00.000Z"),
+  lastActivityAt: new Date("2026-03-03T11:00:00.000Z"),
+  terminalLines: [
+    {
+      id: "line-1",
+      type: "user",
+      content: "Hello",
+      timestamp: new Date("2026-03-03T10:00:00.000Z"),
+      toolName: undefined,
+    },
+    {
+      id: "line-2",
+      type: "assistant",
+      content: "Hi",
+      timestamp: new Date("2026-03-03T10:01:00.000Z"),
+      toolName: undefined,
+    },
+  ],
+});
+
+describe("sessionsStore - loadSessions", () => {
+  it("loads sessions from backend and updates the store", async () => {
+    const sessionList = [{ id: "session-1", name: "Test", message_count: 1, preview: "..." }];
+    setMockInvokeResult("list_sessions", sessionList);
+    await sessionsStore.loadSessions();
+    expect(get(sessionsStore.sessions)).toEqual(sessionList);
+  });
+
+  it("handles errors gracefully", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("list_sessions", new Error("Backend error"));
+    await sessionsStore.loadSessions();
+    expect(spy).toHaveBeenCalledWith("Failed to load sessions:", expect.any(Error));
+    spy.mockRestore();
+  });
+
+  it("sets isLoading to false after completion", async () => {
+    setMockInvokeResult("list_sessions", []);
+    await sessionsStore.loadSessions();
+    expect(get(sessionsStore.isLoading)).toBe(false);
+  });
+});
+
+describe("sessionsStore - loadSession", () => {
+  it("returns session data on success", async () => {
+    const session = makeSavedSession();
+    setMockInvokeResult("load_session", session);
+    const result = await sessionsStore.loadSession("session-1");
+    expect(result).toEqual(session);
+  });
+
+  it("returns null on error", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", new Error("Not found"));
+    const result = await sessionsStore.loadSession("session-1");
+    expect(result).toBeNull();
+    spy.mockRestore();
+  });
+});
+
+describe("sessionsStore - deleteSession", () => {
+  it("deletes session and reloads the session list", async () => {
+    setMockInvokeResult("delete_session", undefined);
+    setMockInvokeResult("list_sessions", []);
+    await sessionsStore.deleteSession("session-1");
+    expect(get(sessionsStore.sessions)).toEqual([]);
+  });
+
+  it("handles errors gracefully", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("delete_session", new Error("Failed"));
+    await sessionsStore.deleteSession("session-1");
+    expect(spy).toHaveBeenCalledWith("Failed to delete session:", expect.any(Error));
+    spy.mockRestore();
+  });
+});
+
+describe("sessionsStore - searchSessions", () => {
+  it("calls loadSessions when query is empty", async () => {
+    setMockInvokeResult("list_sessions", []);
+    await sessionsStore.searchSessions("");
+    expect(get(sessionsStore.sessions)).toEqual([]);
+  });
+
+  it("calls loadSessions when query is whitespace-only", async () => {
+    setMockInvokeResult("list_sessions", []);
+    await sessionsStore.searchSessions("   ");
+    expect(get(sessionsStore.sessions)).toEqual([]);
+  });
+
+  it("searches with the given query", async () => {
+    const results = [{ id: "session-1", name: "Test", message_count: 1, preview: "..." }];
+    setMockInvokeResult("search_sessions", results);
+    await sessionsStore.searchSessions("test");
+    expect(get(sessionsStore.sessions)).toEqual(results);
+  });
+
+  it("updates searchQuery store", async () => {
+    setMockInvokeResult("search_sessions", []);
+    await sessionsStore.searchSessions("hello");
+    expect(get(sessionsStore.searchQuery)).toBe("hello");
+    await sessionsStore.searchSessions("");
+  });
+
+  it("handles search errors gracefully", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("search_sessions", new Error("Search failed"));
+    await sessionsStore.searchSessions("error-query");
+    expect(spy).toHaveBeenCalledWith("Failed to search sessions:", expect.any(Error));
+    spy.mockRestore();
+  });
+});
+
+describe("sessionsStore - clearAllSessions", () => {
+  it("clears all sessions", async () => {
+    setMockInvokeResult("clear_all_sessions", undefined);
+    await sessionsStore.clearAllSessions();
+    expect(get(sessionsStore.sessions)).toEqual([]);
+  });
+
+  it("handles errors gracefully", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("clear_all_sessions", new Error("Failed"));
+    await sessionsStore.clearAllSessions();
+    expect(spy).toHaveBeenCalledWith("Failed to clear sessions:", expect.any(Error));
+    spy.mockRestore();
+  });
+});
+
+describe("sessionsStore - saveConversation", () => {
+  it("saves conversation to backend", async () => {
+    setMockInvokeResult("save_session", undefined);
+    setMockInvokeResult("list_sessions", []);
+    await sessionsStore.saveConversation(makeConversation() as never);
+  });
+
+  it("handles save errors gracefully", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("save_session", new Error("Save failed"));
+    await sessionsStore.saveConversation(makeConversation() as never);
+    expect(spy).toHaveBeenCalledWith("Failed to save session:", expect.any(Error));
+    spy.mockRestore();
+  });
+
+  it("handles empty conversation", async () => {
+    setMockInvokeResult("save_session", undefined);
+    setMockInvokeResult("list_sessions", []);
+    const conv = { ...makeConversation(), terminalLines: [] };
+    await sessionsStore.saveConversation(conv as never);
+  });
+});
+
+describe("sessionsStore - scheduleAutoSave and cancelAutoSave", () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  it("schedules an auto-save after the debounce delay", async () => {
+    setMockInvokeResult("save_session", undefined);
+    setMockInvokeResult("list_sessions", []);
+    sessionsStore.scheduleAutoSave(makeConversation() as never);
+    await vi.advanceTimersByTimeAsync(2001);
+  });
+
+  it("does not auto-save empty conversations", async () => {
+    const conv = { ...makeConversation(), terminalLines: [] };
+    sessionsStore.scheduleAutoSave(conv as never);
+    await vi.advanceTimersByTimeAsync(3000);
+  });
+
+  it("cancels a pending auto-save", () => {
+    const conv = makeConversation();
+    sessionsStore.scheduleAutoSave(conv as never);
+    sessionsStore.cancelAutoSave(conv.id);
+  });
+
+  it("handles cancel when no auto-save is pending", () => {
+    sessionsStore.cancelAutoSave("non-existent-id");
+  });
+
+  it("clears an existing pending auto-save when rescheduled for the same conversation", async () => {
+    setMockInvokeResult("save_session", undefined);
+    setMockInvokeResult("list_sessions", []);
+    const conv = makeConversation();
+    sessionsStore.scheduleAutoSave(conv as never);
+    // Schedule again before timer fires — hits clearTimeout branch (line 487)
+    sessionsStore.scheduleAutoSave(conv as never);
+    await vi.advanceTimersByTimeAsync(2001);
+  });
+});
+
+describe("sessionsStore - exportSessionAsJson", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("returns true on successful export", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session.json");
+    expect(await sessionsStore.exportSessionAsJson("session-1")).toBe(true);
+  });
+
+  it("returns false when session not found", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", null);
+    expect(await sessionsStore.exportSessionAsJson("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+
+  it("returns false when user cancels save dialog", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue(null);
+    expect(await sessionsStore.exportSessionAsJson("session-1")).toBe(false);
+  });
+
+  it("returns false on error", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", new Error("Load failed"));
+    expect(await sessionsStore.exportSessionAsJson("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+
+  it("returns false when writeTextFile throws", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session.json");
+    vi.mocked(writeTextFile).mockRejectedValueOnce(new Error("Disk full"));
+    expect(await sessionsStore.exportSessionAsJson("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+});
+
+describe("sessionsStore - exportSessionAsMarkdown", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("generates markdown with all message types", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    const session = makeSavedSession({
+      messages: [
+        { id: "1", type: "user", content: "User message", timestamp: "2026-03-03T10:00:00Z" },
+        {
+          id: "2",
+          type: "assistant",
+          content: "Assistant reply",
+          timestamp: "2026-03-03T10:01:00Z",
+        },
+        {
+          id: "3",
+          type: "tool_use",
+          content: "Tool input",
+          timestamp: "2026-03-03T10:02:00Z",
+          tool_name: "bash",
+        },
+        { id: "4", type: "tool_result", content: "Tool output", timestamp: "2026-03-03T10:03:00Z" },
+        { id: "5", type: "system", content: "System event", timestamp: "2026-03-03T10:04:00Z" },
+        { id: "6", type: "error", content: "Error message", timestamp: "2026-03-03T10:05:00Z" },
+      ],
+    });
+    setMockInvokeResult("load_session", session);
+    vi.mocked(save).mockResolvedValue("/output/session.md");
+    expect(await sessionsStore.exportSessionAsMarkdown("session-1")).toBe(true);
+    const content = vi.mocked(writeTextFile).mock.calls[0][1] as string;
+    expect(content).toContain("User message");
+    expect(content).toContain("Assistant reply");
+    expect(content).toContain("Tool: bash");
+    expect(content).toContain("Tool input");
+    expect(content).toContain("Tool output");
+    expect(content).toContain("System event");
+    expect(content).toContain("Error message");
+  });
+
+  it("returns false when session not found", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", null);
+    expect(await sessionsStore.exportSessionAsMarkdown("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+
+  it("returns false when user cancels dialog", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue(null);
+    expect(await sessionsStore.exportSessionAsMarkdown("session-1")).toBe(false);
+  });
+
+  it("returns false on error", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", new Error("Load failed"));
+    expect(await sessionsStore.exportSessionAsMarkdown("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+
+  it("returns false when writeTextFile throws", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session.md");
+    vi.mocked(writeTextFile).mockRejectedValueOnce(new Error("Disk full"));
+    expect(await sessionsStore.exportSessionAsMarkdown("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+});
+
+describe("sessionsStore - exportSessionAsHtml (tests escapeHtml + generateHtmlExport)", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("generates HTML and returns true on success", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session.html");
+    expect(await sessionsStore.exportSessionAsHtml("session-1")).toBe(true);
+    const content = vi.mocked(writeTextFile).mock.calls[0][1] as string;
+    expect(content).toContain("<!DOCTYPE html>");
+    expect(content).toContain("Test Session");
+  });
+
+  it("escapes HTML characters in session name", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    setMockInvokeResult("load_session", makeSavedSession({ name: "<Test & 'Session'>" }));
+    vi.mocked(save).mockResolvedValue("/output/session.html");
+    await sessionsStore.exportSessionAsHtml("session-1");
+    const content = vi.mocked(writeTextFile).mock.calls[0][1] as string;
+    expect(content).toContain("&lt;Test &amp; &#039;Session&#039;&gt;");
+    expect(content).not.toContain("<Test & 'Session'>");
+  });
+
+  it("escapes HTML characters in message content", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    setMockInvokeResult(
+      "load_session",
+      makeSavedSession({
+        messages: [
+          {
+            id: "1",
+            type: "user",
+            content: '<script>alert("xss")</script>',
+            timestamp: "2026-03-03T10:00:00Z",
+          },
+        ],
+      })
+    );
+    vi.mocked(save).mockResolvedValue("/output/session.html");
+    await sessionsStore.exportSessionAsHtml("session-1");
+    const content = vi.mocked(writeTextFile).mock.calls[0][1] as string;
+    expect(content).toContain("&lt;script&gt;alert(&quot;xss&quot;)&lt;/script&gt;");
+    expect(content).not.toContain("<script>");
+  });
+
+  it("escapes HTML in tool names", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    setMockInvokeResult(
+      "load_session",
+      makeSavedSession({
+        messages: [
+          {
+            id: "1",
+            type: "tool_use",
+            content: "input",
+            timestamp: "2026-03-03T10:00:00Z",
+            tool_name: "<dangerous>",
+          },
+        ],
+      })
+    );
+    vi.mocked(save).mockResolvedValue("/output/session.html");
+    await sessionsStore.exportSessionAsHtml("session-1");
+    const content = vi.mocked(writeTextFile).mock.calls[0][1] as string;
+    expect(content).toContain("&lt;dangerous&gt;");
+    expect(content).not.toContain("<dangerous>");
+  });
+
+  it("excludes metadata when includeMetadata is false", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session.html");
+    await sessionsStore.exportSessionAsHtml("session-1", false);
+    const content = vi.mocked(writeTextFile).mock.calls[0][1] as string;
+    expect(content).not.toContain('class="metadata"');
+  });
+
+  it("returns false when session not found", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", null);
+    expect(await sessionsStore.exportSessionAsHtml("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+
+  it("returns false when user cancels dialog", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue(null);
+    expect(await sessionsStore.exportSessionAsHtml("session-1")).toBe(false);
+  });
+
+  it("returns false on error", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", new Error("Load failed"));
+    expect(await sessionsStore.exportSessionAsHtml("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+
+  it("returns false when writeTextFile throws", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session.html");
+    vi.mocked(writeTextFile).mockRejectedValueOnce(new Error("Disk full"));
+    expect(await sessionsStore.exportSessionAsHtml("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+});
+
+describe("sessionsStore - exportSessionAsPdf (tests generatePrintableHtml)", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("generates printable HTML and opens it in the browser", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { openPath } = await import("@tauri-apps/plugin-opener");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session-print.html");
+    expect(await sessionsStore.exportSessionAsPdf("session-1")).toBe(true);
+    expect(openPath).toHaveBeenCalledWith("/output/session-print.html");
+    const content = vi.mocked(writeTextFile).mock.calls[0][1] as string;
+    expect(content).toContain("<!DOCTYPE html>");
+  });
+
+  it("excludes metadata when includeMetadata is false", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session-print.html");
+    await sessionsStore.exportSessionAsPdf("session-1", false);
+    expect(vi.mocked(writeTextFile).mock.calls[0][1]).toBeDefined();
+  });
+
+  it("returns false when session not found", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", null);
+    expect(await sessionsStore.exportSessionAsPdf("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+
+  it("returns false when user cancels dialog", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue(null);
+    expect(await sessionsStore.exportSessionAsPdf("session-1")).toBe(false);
+  });
+
+  it("returns false on error", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", new Error("Load failed"));
+    expect(await sessionsStore.exportSessionAsPdf("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+
+  it("returns false when writeTextFile throws", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session-print.html");
+    vi.mocked(writeTextFile).mockRejectedValueOnce(new Error("Disk full"));
+    expect(await sessionsStore.exportSessionAsPdf("session-1")).toBe(false);
+    spy.mockRestore();
+  });
+});
+
+describe("sessionsStore - importSession", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("imports session from JSON file and returns true", async () => {
+    const { open } = await import("@tauri-apps/plugin-dialog");
+    const { readTextFile } = await import("@tauri-apps/plugin-fs");
+    vi.mocked(open).mockResolvedValue("/input/session.json");
+    vi.mocked(readTextFile).mockResolvedValue(JSON.stringify({ session: makeSavedSession() }));
+    setMockInvokeResult("save_session", undefined);
+    setMockInvokeResult("list_sessions", []);
+    expect(await sessionsStore.importSession()).toBe(true);
+  });
+
+  it("returns false when user cancels file dialog", async () => {
+    const { open } = await import("@tauri-apps/plugin-dialog");
+    vi.mocked(open).mockResolvedValue(null);
+    expect(await sessionsStore.importSession()).toBe(false);
+  });
+
+  it("returns false when file has invalid format", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    const { open } = await import("@tauri-apps/plugin-dialog");
+    const { readTextFile } = await import("@tauri-apps/plugin-fs");
+    vi.mocked(open).mockResolvedValue("/input/bad.json");
+    vi.mocked(readTextFile).mockResolvedValue(JSON.stringify({ not_a_session: true }));
+    expect(await sessionsStore.importSession()).toBe(false);
+    spy.mockRestore();
+  });
+
+  it("returns false on error", async () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    const { open } = await import("@tauri-apps/plugin-dialog");
+    vi.mocked(open).mockRejectedValue(new Error("Dialog failed"));
+    expect(await sessionsStore.importSession()).toBe(false);
+    spy.mockRestore();
+  });
+});

src/lib/stores/stats.test.ts

@@ -1,5 +1,7 @@
-import { describe, it, expect, beforeEach, vi } from "vitest";
+import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
 import { get } from "svelte/store";
+import { listen } from "@tauri-apps/api/event";
+import { invoke } from "@tauri-apps/api/core";
 import {
   stats,
   formattedStats,
@@ -9,8 +11,13 @@ import {
   estimateMessageCost,
   formatTokenCount,
   MODEL_PRICING,
+  checkBudget,
+  getBudgetStatusMessage,
+  getRemainingTokenBudget,
+  getRemainingCostBudget,
+  initStatsListener,
 } from "./stats";
-import type { UsageStats, ToolTokenStats } from "./stats";
+import type { UsageStats, ToolTokenStats, BudgetStatus } from "./stats";
 
 // Helper function to create ToolTokenStats for tests
 function toolStats(callCount: number, inputTokens = 0, outputTokens = 0): ToolTokenStats {
@@ -30,6 +37,12 @@ vi.mock("@tauri-apps/api/core", () => ({
   invoke: vi.fn(),
 }));
 
+vi.mock("./costTracking", () => ({
+  costTrackingStore: {
+    refresh: vi.fn().mockResolvedValue([]),
+  },
+}));
+
 describe("stats store", () => {
   beforeEach(() => {
     // Reset stats to default before each test
@@ -600,4 +613,282 @@ describe("stats store", () => {
       expect(MODEL_PRICING["claude-3-haiku-20240307"]).toEqual({ input: 0.25, output: 1.25 });
     });
   });
+
+  describe("checkBudget", () => {
+    const baseStats: UsageStats = {
+      total_input_tokens: 0,
+      total_output_tokens: 0,
+      total_cost_usd: 0,
+      session_input_tokens: 500,
+      session_output_tokens: 500,
+      session_cost_usd: 0.5,
+      model: null,
+      messages_exchanged: 0,
+      session_messages_exchanged: 0,
+      code_blocks_generated: 0,
+      session_code_blocks_generated: 0,
+      files_edited: 0,
+      session_files_edited: 0,
+      files_created: 0,
+      session_files_created: 0,
+      tools_usage: {},
+      session_tools_usage: {},
+      session_duration_seconds: 0,
+      context_tokens_used: 0,
+      context_window_limit: 200000,
+      context_utilisation_percent: 0,
+      potential_cache_hits: 0,
+      potential_cache_savings_tokens: 0,
+    };
+
+    it("returns ok when budget is disabled", () => {
+      const result = checkBudget(baseStats, false, 100, 1.0, 0.8);
+      expect(result).toEqual({ type: "ok" });
+    });
+
+    it("returns ok when under all budgets", () => {
+      const result = checkBudget(baseStats, true, 10000, 10.0, 0.8);
+      expect(result).toEqual({ type: "ok" });
+    });
+
+    it("returns exceeded when token budget is reached", () => {
+      const result = checkBudget(baseStats, true, 1000, null, 0.8);
+      expect(result).toEqual({ type: "exceeded", budget_type: "token" });
+    });
+
+    it("returns warning when token usage is above threshold", () => {
+      // session tokens = 1000, budget = 1100, threshold = 0.8 → 1000/1100 ≈ 0.909 > 0.8
+      const result = checkBudget(baseStats, true, 1100, null, 0.8);
+      expect(result.type).toBe("warning");
+      if (result.type === "warning") {
+        expect(result.budget_type).toBe("token");
+        expect(result.percent_used).toBeGreaterThan(80);
+      }
+    });
+
+    it("returns exceeded when cost budget is reached", () => {
+      const result = checkBudget(baseStats, true, null, 0.5, 0.8);
+      expect(result).toEqual({ type: "exceeded", budget_type: "cost" });
+    });
+
+    it("returns warning when cost usage is above threshold", () => {
+      // session cost = 0.5, budget = 0.55, threshold = 0.8 → 0.5/0.55 ≈ 0.909 > 0.8
+      const result = checkBudget(baseStats, true, null, 0.55, 0.8);
+      expect(result.type).toBe("warning");
+      if (result.type === "warning") {
+        expect(result.budget_type).toBe("cost");
+      }
+    });
+
+    it("checks token budget before cost budget", () => {
+      // Both budgets exceeded, but token should be reported first
+      const result = checkBudget(baseStats, true, 500, 0.1, 0.8);
+      expect(result).toEqual({ type: "exceeded", budget_type: "token" });
+    });
+
+    it("returns ok when no budgets are set", () => {
+      const result = checkBudget(baseStats, true, null, null, 0.8);
+      expect(result).toEqual({ type: "ok" });
+    });
+  });
+
+  describe("getBudgetStatusMessage", () => {
+    it("returns null for ok status", () => {
+      const status: BudgetStatus = { type: "ok" };
+      expect(getBudgetStatusMessage(status)).toBeNull();
+    });
+
+    it("returns exceeded message for token budget", () => {
+      const status: BudgetStatus = { type: "exceeded", budget_type: "token" };
+      const message = getBudgetStatusMessage(status);
+      expect(message).toContain("token");
+      expect(message).toContain("exceeded");
+    });
+
+    it("returns exceeded message for cost budget", () => {
+      const status: BudgetStatus = { type: "exceeded", budget_type: "cost" };
+      const message = getBudgetStatusMessage(status);
+      expect(message).toContain("cost");
+      expect(message).toContain("exceeded");
+    });
+
+    it("returns warning message with percentage for token budget", () => {
+      const status: BudgetStatus = { type: "warning", budget_type: "token", percent_used: 85.5 };
+      const message = getBudgetStatusMessage(status);
+      expect(message).toContain("token");
+      expect(message).toContain("86%");
+    });
+
+    it("returns warning message with percentage for cost budget", () => {
+      const status: BudgetStatus = { type: "warning", budget_type: "cost", percent_used: 90 };
+      const message = getBudgetStatusMessage(status);
+      expect(message).toContain("cost");
+      expect(message).toContain("90%");
+    });
+  });
+
+  describe("getRemainingTokenBudget", () => {
+    const baseStats: UsageStats = {
+      total_input_tokens: 0,
+      total_output_tokens: 0,
+      total_cost_usd: 0,
+      session_input_tokens: 300,
+      session_output_tokens: 200,
+      session_cost_usd: 0,
+      model: null,
+      messages_exchanged: 0,
+      session_messages_exchanged: 0,
+      code_blocks_generated: 0,
+      session_code_blocks_generated: 0,
+      files_edited: 0,
+      session_files_edited: 0,
+      files_created: 0,
+      session_files_created: 0,
+      tools_usage: {},
+      session_tools_usage: {},
+      session_duration_seconds: 0,
+      context_tokens_used: 0,
+      context_window_limit: 200000,
+      context_utilisation_percent: 0,
+      potential_cache_hits: 0,
+      potential_cache_savings_tokens: 0,
+    };
+
+    it("returns null when no token budget is set", () => {
+      expect(getRemainingTokenBudget(baseStats, null)).toBeNull();
+    });
+
+    it("returns the remaining tokens when under budget", () => {
+      // session tokens = 500, budget = 1000 → remaining = 500
+      expect(getRemainingTokenBudget(baseStats, 1000)).toBe(500);
+    });
+
+    it("returns 0 when at or over budget", () => {
+      expect(getRemainingTokenBudget(baseStats, 500)).toBe(0);
+      expect(getRemainingTokenBudget(baseStats, 400)).toBe(0);
+    });
+  });
+
+  describe("getRemainingCostBudget", () => {
+    const baseStats: UsageStats = {
+      total_input_tokens: 0,
+      total_output_tokens: 0,
+      total_cost_usd: 0,
+      session_input_tokens: 0,
+      session_output_tokens: 0,
+      session_cost_usd: 0.3,
+      model: null,
+      messages_exchanged: 0,
+      session_messages_exchanged: 0,
+      code_blocks_generated: 0,
+      session_code_blocks_generated: 0,
+      files_edited: 0,
+      session_files_edited: 0,
+      files_created: 0,
+      session_files_created: 0,
+      tools_usage: {},
+      session_tools_usage: {},
+      session_duration_seconds: 0,
+      context_tokens_used: 0,
+      context_window_limit: 200000,
+      context_utilisation_percent: 0,
+      potential_cache_hits: 0,
+      potential_cache_savings_tokens: 0,
+    };
+
+    it("returns null when no cost budget is set", () => {
+      expect(getRemainingCostBudget(baseStats, null)).toBeNull();
+    });
+
+    it("returns the remaining cost when under budget", () => {
+      // session cost = 0.3, budget = 1.0 → remaining = 0.7
+      expect(getRemainingCostBudget(baseStats, 1.0)).toBeCloseTo(0.7, 5);
+    });
+
+    it("returns 0 when at or over budget", () => {
+      expect(getRemainingCostBudget(baseStats, 0.3)).toBe(0);
+      expect(getRemainingCostBudget(baseStats, 0.2)).toBe(0);
+    });
+  });
+
+  describe("initStatsListener", () => {
+    const emptyStats: UsageStats = {
+      total_input_tokens: 0,
+      total_output_tokens: 0,
+      total_cost_usd: 0,
+      session_input_tokens: 0,
+      session_output_tokens: 0,
+      session_cost_usd: 0,
+      model: null,
+      messages_exchanged: 0,
+      session_messages_exchanged: 0,
+      code_blocks_generated: 0,
+      session_code_blocks_generated: 0,
+      files_edited: 0,
+      session_files_edited: 0,
+      files_created: 0,
+      session_files_created: 0,
+      tools_usage: {},
+      session_tools_usage: {},
+      session_duration_seconds: 0,
+      context_tokens_used: 0,
+      context_window_limit: 200000,
+      context_utilisation_percent: 0,
+      potential_cache_hits: 0,
+      potential_cache_savings_tokens: 0,
+    };
+
+    afterEach(() => {
+      vi.resetAllMocks();
+    });
+
+    it("registers a listener for the claude:stats event", async () => {
+      vi.mocked(listen).mockResolvedValue(vi.fn());
+      vi.mocked(invoke).mockResolvedValue(emptyStats);
+
+      await initStatsListener();
+
+      expect(listen).toHaveBeenCalledWith("claude:stats", expect.any(Function));
+    });
+
+    it("updates the stats store when the listener callback fires", async () => {
+      let capturedCallback: ((event: unknown) => void) | undefined;
+      vi.mocked(listen).mockImplementation(async (_event, callback) => {
+        capturedCallback = callback as (event: unknown) => void;
+        return () => {};
+      });
+      vi.mocked(invoke).mockResolvedValue(emptyStats);
+
+      await initStatsListener();
+
+      const newStats = { ...emptyStats, total_input_tokens: 9999 };
+      capturedCallback!({ payload: { stats: newStats } });
+
+      expect(get(stats).total_input_tokens).toBe(9999);
+    });
+
+    it("loads persisted stats from the backend on initialisation", async () => {
+      const persistedStats = { ...emptyStats, total_input_tokens: 5000 };
+      vi.mocked(listen).mockResolvedValue(vi.fn());
+      vi.mocked(invoke).mockResolvedValue(persistedStats);
+
+      await initStatsListener();
+
+      expect(invoke).toHaveBeenCalledWith("get_persisted_stats");
+      expect(get(stats).total_input_tokens).toBe(5000);
+    });
+
+    it("handles a failed invoke gracefully and logs the error", async () => {
+      const error = new Error("Failed to get stats");
+      vi.mocked(listen).mockResolvedValue(vi.fn());
+      vi.mocked(invoke).mockRejectedValue(error);
+
+      const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+
+      await initStatsListener();
+
+      expect(consoleErrorSpy).toHaveBeenCalledWith("Failed to load initial stats:", error);
+      consoleErrorSpy.mockRestore();
+    });
+  });
 });

src/lib/stores/todos.test.ts

@@ -0,0 +1,93 @@
+import { describe, it, expect, beforeEach } from "vitest";
+import { get } from "svelte/store";
+import { emitMockEvent } from "../../../vitest.setup";
+import { todos, initializeTodoListener, cleanupTodoListener } from "./todos";
+import type { TodoItem } from "./todos";
+
+describe("todos store", () => {
+  beforeEach(() => {
+    cleanupTodoListener();
+    todos.clear();
+  });
+
+  describe("initial state", () => {
+    it("starts with an empty list", () => {
+      expect(get(todos)).toEqual([]);
+    });
+  });
+
+  describe("set and clear", () => {
+    it("can set todos directly", () => {
+      const items: TodoItem[] = [
+        { content: "Task 1", status: "pending", activeForm: "Doing task 1" },
+        { content: "Task 2", status: "in_progress", activeForm: "Doing task 2" },
+      ];
+      todos.set(items);
+      expect(get(todos)).toEqual(items);
+    });
+
+    it("clear resets to empty array", () => {
+      todos.set([{ content: "Task", status: "completed", activeForm: "Doing task" }]);
+      todos.clear();
+      expect(get(todos)).toEqual([]);
+    });
+  });
+
+  describe("update", () => {
+    it("can update todos with a callback", () => {
+      const initial: TodoItem[] = [
+        { content: "Task 1", status: "pending", activeForm: "Doing task 1" },
+      ];
+      todos.set(initial);
+      todos.update((current) => [
+        ...current,
+        { content: "Task 2", status: "completed", activeForm: "Doing task 2" },
+      ]);
+      expect(get(todos)).toHaveLength(2);
+    });
+  });
+
+  describe("initializeTodoListener", () => {
+    it("listens for claude:todo-update events", async () => {
+      await initializeTodoListener();
+
+      const newTodos: TodoItem[] = [
+        { content: "Backend task", status: "in_progress", activeForm: "Running backend task" },
+      ];
+      emitMockEvent("claude:todo-update", { todos: newTodos });
+
+      expect(get(todos)).toEqual(newTodos);
+    });
+
+    it("does not register a duplicate listener when called twice", async () => {
+      await initializeTodoListener();
+      await initializeTodoListener();
+
+      const newTodos: TodoItem[] = [
+        { content: "Task", status: "pending", activeForm: "Doing task" },
+      ];
+      emitMockEvent("claude:todo-update", { todos: newTodos });
+
+      // Should only have been set once (not doubled)
+      expect(get(todos)).toEqual(newTodos);
+    });
+  });
+
+  describe("cleanupTodoListener", () => {
+    it("stops listening for events after cleanup", async () => {
+      await initializeTodoListener();
+      cleanupTodoListener();
+
+      emitMockEvent("claude:todo-update", {
+        todos: [{ content: "Task", status: "pending", activeForm: "Doing task" }],
+      });
+
+      // Should not have been updated since we cleaned up
+      expect(get(todos)).toEqual([]);
+    });
+
+    it("is safe to call when not initialised", () => {
+      expect(() => cleanupTodoListener()).not.toThrow();
+    });
+  });
+});