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/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();
+    });
+  });
+});