feat: major feature additions and improvements (#135)

## Summary

This PR includes major feature additions, bug fixes, comprehensive testing improvements, and responsive design enhancements!

## New Features ✨

### Plugin & MCP Management (#133, #134)
- **Plugin Management Panel**: Install, uninstall, enable/disable, and update plugins
- **MCP Server Management Panel**: Add/remove MCP servers, view detailed configuration
- **Marketplace Management**: Add/remove plugin marketplaces from GitHub
- Backend commands for full CLI integration (`list_plugins`, `install_plugin`, `add_mcp_server`, etc.)
- Beautiful UI with proper loading states, error handling, and theme support

### Visual Todo List Panel (#132)
- Real-time todo list display when Hikari uses the `TodoWrite` tool
- Shows pending/in-progress/completed status with visual indicators
- Progress bar and completion count
- Automatically clears on disconnect
- Theme-aware styling

### Clear Session History Button (#130)
- "Clear All Sessions" button in Session History panel
- Confirmation dialog with session count
- Keyboard support and accessibility features
- Gives users control over disk usage

### CLI Version Display (#131)
- Displays Claude CLI version in status bar
- Auto-polls every 30 seconds for updates
- Useful for debugging and feature compatibility

## Bug Fixes 🐛

### Stats Panel Scrolling (#136)
- **Fixed stats panel overflow**: Added scrollable container with `max-height` constraint
- Stats panel now scrolls when content (Tools Used, Historical Costs, Budget sections) gets too long
- Prevents content from overflowing off screen

### Agent Monitor Fixes (#122)
- **Fixed agents stuck in "running" state**: Added `SubagentStop` hook parsing
- **Fixed agents persisting after disconnect**: Call `clearConversation()` on disconnect
- **Fixed "Kill All" button**: Now properly marks all agents as errored
- **Fixed badge persisting after tab close**: Cleanup agents when conversation is deleted
- Comprehensive tests for agent lifecycle management

### Discord RPC Cleanup (#129)
- Removed file-based logging for Discord RPC
- Replaced with proper `tracing` framework usage
- Reduces disk usage and eliminates maintenance burden

### Close Modal Bug Fix (#128)
- Fixed close confirmation modal not triggering after Discord RPC refactor
- Removed frontend calls to deleted `log_discord_rpc` command
- Modal now works correctly after all operations

### Responsive Design Fixes (#118)
- Fixed top navigation icons getting cut off at small screen widths
- Fixed Connect button disappearing on narrow screens
- Fixed bottom status info (clock, CLI version) getting cut off
- Added flex-wrap and mobile-optimised layouts
- Icons-only mode on screens < 640px
- Vertical stacking on screens < 768px

## Testing Improvements 🧪

### Comprehensive Test Coverage (#114)
- **417 backend tests** (up from 408)
- **387 frontend tests** (up from 363)
- **61%+ backend code coverage**
- Added E2E integration tests for cross-platform notification commands
- New test files: `agents.test.ts`, comprehensive CLI parsing tests
- Tests for `debug_logger.rs`, `bridge_manager.rs`, `notifications.rs`
- Console mocking for cleaner test output
- Fixed flaky frontend tests

### Testing Documentation
- Updated CLAUDE.md with comprehensive testing guidelines
- Documented mocking approaches (console mocking, E2E command structure testing)
- Added step-by-step guide for adding tests to new features
- Goal to maintain ~100% test coverage documented

## Closes

Closes #114
Closes #118
Closes #122
Closes #128
Closes #129
Closes #130
Closes #131
Closes #132
Closes #133
Closes #134
Closes #136

## Technical Details

- All new backend commands properly registered in `lib.rs`
- CLI output parsing with comprehensive test coverage
- Cross-platform compatibility verified through E2E tests (Linux CI can test Windows commands)
- Theme-aware UI components using CSS variables throughout
- Proper TypeScript types for all new stores and components
- ESLint and Prettier compliant
- All Clippy warnings addressed

✨ This PR was created with help from Hikari~ 🌸

Reviewed-on: #135
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src/lib/components/PluginManagementPanel.svelte

@@ -0,0 +1,447 @@
+<script lang="ts">
+  import { invoke } from "@tauri-apps/api/core";
+  import { onMount } from "svelte";
+  import { Download, Trash2, Power, PowerOff, RefreshCw } from "lucide-svelte";
+
+  interface Props {
+    onClose: () => void;
+  }
+
+  interface PluginInfo {
+    name: string;
+    version: string;
+    description: string | null;
+    enabled: boolean;
+  }
+
+  interface MarketplaceInfo {
+    name: string;
+    source: string;
+  }
+
+  const { onClose }: Props = $props();
+
+  let plugins = $state<PluginInfo[]>([]);
+  let marketplaces = $state<MarketplaceInfo[]>([]);
+  let isLoading = $state(true);
+  let isLoadingMarketplaces = $state(false);
+  let error = $state<string | null>(null);
+  let newPluginName = $state("");
+  let isInstalling = $state(false);
+  let actionInProgress = $state<string | null>(null);
+  let showMarketplaces = $state(false);
+  let newMarketplaceSource = $state("");
+  let isAddingMarketplace = $state(false);
+
+  async function loadPlugins(): Promise<void> {
+    try {
+      isLoading = true;
+      error = null;
+      plugins = await invoke<PluginInfo[]>("list_plugins");
+    } catch (e) {
+      error = `Failed to load plugins: ${e}`;
+      console.error(error);
+    } finally {
+      isLoading = false;
+    }
+  }
+
+  async function loadMarketplaces(): Promise<void> {
+    try {
+      isLoadingMarketplaces = true;
+      error = null;
+      marketplaces = await invoke<MarketplaceInfo[]>("list_marketplaces");
+    } catch (e) {
+      error = `Failed to load marketplaces: ${e}`;
+      console.error(error);
+    } finally {
+      isLoadingMarketplaces = false;
+    }
+  }
+
+  async function installPlugin(): Promise<void> {
+    if (!newPluginName.trim()) return;
+
+    try {
+      isInstalling = true;
+      error = null;
+      await invoke("install_plugin", { pluginName: newPluginName.trim() });
+      newPluginName = "";
+      await loadPlugins();
+    } catch (e) {
+      error = `Failed to install plugin: ${e}`;
+      console.error(error);
+    } finally {
+      isInstalling = false;
+    }
+  }
+
+  async function uninstallPlugin(pluginName: string): Promise<void> {
+    try {
+      actionInProgress = pluginName;
+      error = null;
+      await invoke("uninstall_plugin", { pluginName });
+      await loadPlugins();
+    } catch (e) {
+      error = `Failed to uninstall plugin: ${e}`;
+      console.error(error);
+    } finally {
+      actionInProgress = null;
+    }
+  }
+
+  async function togglePlugin(plugin: PluginInfo): Promise<void> {
+    try {
+      actionInProgress = plugin.name;
+      error = null;
+      if (plugin.enabled) {
+        await invoke("disable_plugin", { pluginName: plugin.name });
+      } else {
+        await invoke("enable_plugin", { pluginName: plugin.name });
+      }
+      await loadPlugins();
+    } catch (e) {
+      error = `Failed to ${plugin.enabled ? "disable" : "enable"} plugin: ${e}`;
+      console.error(error);
+    } finally {
+      actionInProgress = null;
+    }
+  }
+
+  async function updatePlugin(pluginName: string): Promise<void> {
+    try {
+      actionInProgress = pluginName;
+      error = null;
+      await invoke("update_plugin", { pluginName });
+      await loadPlugins();
+    } catch (e) {
+      error = `Failed to update plugin: ${e}`;
+      console.error(error);
+    } finally {
+      actionInProgress = null;
+    }
+  }
+
+  async function addMarketplace(): Promise<void> {
+    if (!newMarketplaceSource.trim()) return;
+
+    try {
+      isAddingMarketplace = true;
+      error = null;
+      await invoke("add_marketplace", { source: newMarketplaceSource.trim() });
+      newMarketplaceSource = "";
+      await loadMarketplaces();
+    } catch (e) {
+      error = `Failed to add marketplace: ${e}`;
+      console.error(error);
+    } finally {
+      isAddingMarketplace = false;
+    }
+  }
+
+  async function removeMarketplace(name: string): Promise<void> {
+    try {
+      actionInProgress = name;
+      error = null;
+      await invoke("remove_marketplace", { name });
+      await loadMarketplaces();
+    } catch (e) {
+      error = `Failed to remove marketplace: ${e}`;
+      console.error(error);
+    } finally {
+      actionInProgress = null;
+    }
+  }
+
+  onMount(() => {
+    loadPlugins();
+  });
+</script>
+
+<div
+  class="fixed top-0 right-0 h-full w-[600px] bg-[var(--bg-primary)] border-l border-[var(--accent-primary)]/30 shadow-2xl flex flex-col z-50"
+>
+  <!-- Header -->
+  <div class="flex items-center justify-between p-4 border-b border-[var(--accent-primary)]/30">
+    <div class="flex items-center gap-3">
+      <div class="text-[var(--accent-primary)]">
+        <svg
+          xmlns="http://www.w3.org/2000/svg"
+          class="h-6 w-6"
+          fill="none"
+          viewBox="0 0 24 24"
+          stroke="currentColor"
+        >
+          <path
+            stroke-linecap="round"
+            stroke-linejoin="round"
+            stroke-width="2"
+            d="M20 7l-8-4-8 4m16 0l-8 4m8-4v10l-8 4m0-10L4 7m8 4v10M4 7v10l8 4"
+          />
+        </svg>
+      </div>
+      <div>
+        <h2 class="text-lg font-semibold text-[var(--text-primary)]">Plugin Management</h2>
+        <p class="text-xs text-[var(--text-secondary)]">
+          {plugins.length} plugin{plugins.length !== 1 ? "s" : ""} installed
+        </p>
+      </div>
+    </div>
+    <button
+      onclick={onClose}
+      class="text-[var(--text-secondary)] hover:text-[var(--text-primary)] transition-colors p-1 rounded-lg hover:bg-[var(--bg-secondary)]"
+      aria-label="Close plugin panel"
+    >
+      <svg
+        xmlns="http://www.w3.org/2000/svg"
+        class="h-5 w-5"
+        viewBox="0 0 20 20"
+        fill="currentColor"
+      >
+        <path
+          fill-rule="evenodd"
+          d="M4.293 4.293a1 1 0 011.414 0L10 8.586l4.293-4.293a1 1 0 111.414 1.414L11.414 10l4.293 4.293a1 1 0 01-1.414 1.414L10 11.414l-4.293 4.293a1 1 0 01-1.414-1.414L8.586 10 4.293 5.707a1 1 0 010-1.414z"
+          clip-rule="evenodd"
+        />
+      </svg>
+    </button>
+  </div>
+
+  <!-- Install Plugin Section -->
+  <div class="p-4 border-b border-[var(--border-color)]">
+    <h3 class="text-sm font-medium text-[var(--text-primary)] mb-2">Install New Plugin</h3>
+    <p class="text-xs text-[var(--text-secondary)] mb-3">
+      Enter plugin name (e.g., "macrodata" or "macrodata@macrodata" for specific marketplace)
+    </p>
+    <div class="flex gap-2">
+      <input
+        type="text"
+        bind:value={newPluginName}
+        placeholder="plugin-name or plugin@marketplace"
+        class="flex-1 px-3 py-2 bg-[var(--bg-secondary)] border border-[var(--border-color)] rounded-lg text-[var(--text-primary)] text-sm focus:outline-none focus:border-[var(--accent-primary)]"
+        onkeydown={(e) => e.key === "Enter" && installPlugin()}
+        disabled={isInstalling}
+      />
+      <button
+        onclick={installPlugin}
+        disabled={isInstalling || !newPluginName.trim()}
+        class="px-4 py-2 bg-[var(--accent-primary)] text-white rounded-lg text-sm font-medium hover:opacity-80 disabled:opacity-40 disabled:cursor-not-allowed flex items-center gap-2"
+      >
+        {#if isInstalling}
+          <RefreshCw class="w-4 h-4 animate-spin" />
+        {:else}
+          <Download class="w-4 h-4" />
+        {/if}
+        Install
+      </button>
+    </div>
+  </div>
+
+  <!-- Marketplace Management Section -->
+  <div class="p-4 border-b border-[var(--border-color)]">
+    <button
+      onclick={() => {
+        showMarketplaces = !showMarketplaces;
+        if (showMarketplaces && marketplaces.length === 0) {
+          loadMarketplaces();
+        }
+      }}
+      class="w-full text-left flex items-center justify-between text-sm font-medium text-[var(--text-primary)] hover:text-[var(--accent-primary)] transition-colors"
+    >
+      <span>Manage Marketplaces</span>
+      <svg
+        xmlns="http://www.w3.org/2000/svg"
+        class="h-4 w-4 transition-transform"
+        class:rotate-180={showMarketplaces}
+        fill="none"
+        viewBox="0 0 24 24"
+        stroke="currentColor"
+      >
+        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M19 9l-7 7-7-7" />
+      </svg>
+    </button>
+
+    {#if showMarketplaces}
+      <div class="mt-3 space-y-3">
+        <!-- Add Marketplace Form -->
+        <div>
+          <p class="text-xs text-[var(--text-secondary)] mb-2">
+            Add a marketplace from GitHub (e.g., "ascorbic/macrodata")
+          </p>
+          <div class="flex gap-2">
+            <input
+              type="text"
+              bind:value={newMarketplaceSource}
+              placeholder="owner/repo"
+              class="flex-1 px-3 py-2 bg-[var(--bg-secondary)] border border-[var(--border-color)] rounded-lg text-[var(--text-primary)] text-sm focus:outline-none focus:border-[var(--accent-primary)]"
+              onkeydown={(e) => e.key === "Enter" && addMarketplace()}
+              disabled={isAddingMarketplace}
+            />
+            <button
+              onclick={addMarketplace}
+              disabled={isAddingMarketplace || !newMarketplaceSource.trim()}
+              class="px-4 py-2 bg-[var(--accent-primary)] text-white rounded-lg text-sm font-medium hover:opacity-80 disabled:opacity-40 disabled:cursor-not-allowed flex items-center gap-2"
+            >
+              {#if isAddingMarketplace}
+                <RefreshCw class="w-4 h-4 animate-spin" />
+              {:else}
+                <Download class="w-4 h-4" />
+              {/if}
+              Add
+            </button>
+          </div>
+        </div>
+
+        <!-- Marketplaces List -->
+        {#if isLoadingMarketplaces}
+          <div class="flex items-center justify-center py-4">
+            <RefreshCw class="w-5 h-5 animate-spin text-[var(--text-secondary)]" />
+          </div>
+        {:else if marketplaces.length > 0}
+          <div class="space-y-2">
+            {#each marketplaces as marketplace (marketplace.name)}
+              <div
+                class="bg-[var(--bg-secondary)]/50 rounded-lg p-3 border border-[var(--border-color)]"
+              >
+                <div class="flex items-start justify-between">
+                  <div class="flex-1">
+                    <h4 class="font-medium text-[var(--text-primary)]">{marketplace.name}</h4>
+                    <p class="text-xs text-[var(--text-secondary)] mt-1">{marketplace.source}</p>
+                  </div>
+                  <button
+                    onclick={() => removeMarketplace(marketplace.name)}
+                    disabled={actionInProgress === marketplace.name}
+                    class="px-2 py-1 text-red-400 hover:bg-red-500/20 rounded transition-colors disabled:opacity-40"
+                  >
+                    <Trash2 class="w-4 h-4" />
+                  </button>
+                </div>
+              </div>
+            {/each}
+          </div>
+        {:else}
+          <p class="text-sm text-[var(--text-secondary)] text-center py-4">
+            No marketplaces configured
+          </p>
+        {/if}
+      </div>
+    {/if}
+  </div>
+
+  <!-- Error Display -->
+  {#if error}
+    <div class="mx-4 mt-4 p-3 bg-red-500/20 border border-red-500/30 rounded-lg">
+      <p class="text-sm text-red-400">{error}</p>
+    </div>
+  {/if}
+
+  <!-- Plugins List -->
+  <div class="flex-1 overflow-y-auto p-4">
+    {#if isLoading}
+      <div class="flex items-center justify-center h-full text-[var(--text-secondary)]">
+        <RefreshCw class="w-8 h-8 animate-spin" />
+      </div>
+    {:else if plugins.length === 0}
+      <div class="flex flex-col items-center justify-center h-full text-[var(--text-secondary)]">
+        <svg
+          xmlns="http://www.w3.org/2000/svg"
+          class="h-16 w-16 mb-4 opacity-50"
+          fill="none"
+          viewBox="0 0 24 24"
+          stroke="currentColor"
+        >
+          <path
+            stroke-linecap="round"
+            stroke-linejoin="round"
+            stroke-width="2"
+            d="M20 7l-8-4-8 4m16 0l-8 4m8-4v10l-8 4m0-10L4 7m8 4v10M4 7v10l8 4"
+          />
+        </svg>
+        <p class="text-center">No plugins installed</p>
+        <p class="text-sm text-center mt-2">Install a plugin using the form above</p>
+      </div>
+    {:else}
+      <div class="space-y-3">
+        {#each plugins as plugin (plugin.name)}
+          <div
+            class="bg-[var(--bg-secondary)]/50 rounded-lg p-4 border border-[var(--border-color)] hover:border-[var(--accent-primary)]/50 transition-all"
+          >
+            <div class="flex items-start justify-between mb-2">
+              <div class="flex-1">
+                <h4 class="font-medium text-[var(--text-primary)] flex items-center gap-2">
+                  {plugin.name}
+                  {#if plugin.enabled}
+                    <span
+                      class="px-2 py-0.5 bg-[var(--success-color)]/20 text-[var(--success-color)] text-xs rounded border border-[var(--success-color)]/30"
+                    >
+                      Enabled
+                    </span>
+                  {:else}
+                    <span
+                      class="px-2 py-0.5 bg-[var(--text-secondary)]/20 text-[var(--text-secondary)] text-xs rounded border border-[var(--border-color)]"
+                    >
+                      Disabled
+                    </span>
+                  {/if}
+                </h4>
+                <p class="text-xs text-[var(--text-secondary)] mt-1">v{plugin.version}</p>
+                {#if plugin.description}
+                  <p class="text-sm text-[var(--text-secondary)] mt-2">{plugin.description}</p>
+                {/if}
+              </div>
+            </div>
+
+            <div class="flex gap-2 mt-3">
+              <button
+                onclick={() => togglePlugin(plugin)}
+                disabled={actionInProgress === plugin.name}
+                class="flex-1 px-3 py-1.5 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded text-sm text-[var(--text-primary)] hover:border-[var(--accent-primary)]/50 transition-colors disabled:opacity-40 disabled:cursor-not-allowed flex items-center justify-center gap-2"
+              >
+                {#if plugin.enabled}
+                  <PowerOff class="w-4 h-4" />
+                  Disable
+                {:else}
+                  <Power class="w-4 h-4" />
+                  Enable
+                {/if}
+              </button>
+
+              <button
+                onclick={() => updatePlugin(plugin.name)}
+                disabled={actionInProgress === plugin.name}
+                class="px-3 py-1.5 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded text-sm text-[var(--text-primary)] hover:border-[var(--accent-primary)]/50 transition-colors disabled:opacity-40 disabled:cursor-not-allowed flex items-center gap-2"
+              >
+                <RefreshCw class="w-4 h-4" />
+                Update
+              </button>
+
+              <button
+                onclick={() => uninstallPlugin(plugin.name)}
+                disabled={actionInProgress === plugin.name}
+                class="px-3 py-1.5 bg-red-500/20 border border-red-500/30 rounded text-sm text-red-400 hover:bg-red-500/30 transition-colors disabled:opacity-40 disabled:cursor-not-allowed flex items-center gap-2"
+              >
+                <Trash2 class="w-4 h-4" />
+                Uninstall
+              </button>
+            </div>
+          </div>
+        {/each}
+      </div>
+    {/if}
+  </div>
+</div>
+
+<style>
+  @keyframes spin {
+    from {
+      transform: rotate(0deg);
+    }
+    to {
+      transform: rotate(360deg);
+    }
+  }
+
+  .animate-spin {
+    animation: spin 1s linear infinite;
+  }
+</style>