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/McpManagementPanel.svelte

@@ -0,0 +1,433 @@
+<script lang="ts">
+  import { invoke } from "@tauri-apps/api/core";
+  import { onMount } from "svelte";
+  import { Trash2, RefreshCw, Server, Globe, Terminal } from "lucide-svelte";
+
+  interface Props {
+    onClose: () => void;
+  }
+
+  interface McpServerInfo {
+    name: string;
+    command: string | null;
+    url: string | null;
+    transport: string; // "stdio", "http", or "sse"
+    env: Record<string, string> | null;
+    status: string | null; // "Connected" or "Failed to connect"
+  }
+
+  const { onClose }: Props = $props();
+
+  let servers = $state<McpServerInfo[]>([]);
+  let isLoading = $state(true);
+  let error = $state<string | null>(null);
+  let selectedServer = $state<McpServerInfo | null>(null);
+  let isLoadingDetails = $state(false);
+  let actionInProgress = $state<string | null>(null);
+  let showAddForm = $state(false);
+  let serverDetails = $state<string>("");
+
+  // Add server form fields
+  let newServerName = $state("");
+  let newServerUrl = $state("");
+  let newServerTransport = $state("stdio");
+  let isAdding = $state(false);
+
+  async function loadServers(): Promise<void> {
+    try {
+      isLoading = true;
+      error = null;
+      servers = await invoke<McpServerInfo[]>("list_mcp_servers");
+    } catch (e) {
+      error = `Failed to load MCP servers: ${e}`;
+      console.error(error);
+    } finally {
+      isLoading = false;
+    }
+  }
+
+  async function loadServerDetails(name: string): Promise<void> {
+    try {
+      isLoadingDetails = true;
+      error = null;
+      selectedServer = await invoke<McpServerInfo>("get_mcp_server", { name });
+      serverDetails = await invoke<string>("get_mcp_server_details", { name });
+    } catch (e) {
+      error = `Failed to load server details: ${e}`;
+      console.error(error);
+    } finally {
+      isLoadingDetails = false;
+    }
+  }
+
+  async function removeServer(name: string): Promise<void> {
+    try {
+      actionInProgress = name;
+      error = null;
+      await invoke("remove_mcp_server", { name });
+      if (selectedServer?.name === name) {
+        selectedServer = null;
+        serverDetails = "";
+      }
+      await loadServers();
+    } catch (e) {
+      error = `Failed to remove server: ${e}`;
+      console.error(error);
+    } finally {
+      actionInProgress = null;
+    }
+  }
+
+  async function addServer(): Promise<void> {
+    if (!newServerName.trim() || !newServerUrl.trim()) return;
+
+    try {
+      isAdding = true;
+      error = null;
+      await invoke("add_mcp_server", {
+        name: newServerName.trim(),
+        commandOrUrl: newServerUrl.trim(),
+        transport: newServerTransport,
+        envVars: null,
+        headers: null,
+      });
+      newServerName = "";
+      newServerUrl = "";
+      newServerTransport = "stdio";
+      showAddForm = false;
+      await loadServers();
+    } catch (e) {
+      error = `Failed to add server: ${e}`;
+      console.error(error);
+    } finally {
+      isAdding = false;
+    }
+  }
+
+  function getTransportIcon(transport: string) {
+    switch (transport) {
+      case "http":
+        return Globe;
+      case "stdio":
+        return Terminal;
+      case "sse":
+        return Server;
+      default:
+        return Server;
+    }
+  }
+
+  function getTransportColor(transport: string) {
+    switch (transport) {
+      case "http":
+        return "text-blue-400";
+      case "stdio":
+        return "text-green-400";
+      case "sse":
+        return "text-purple-400";
+      default:
+        return "text-[var(--text-secondary)]";
+    }
+  }
+
+  onMount(() => {
+    loadServers();
+  });
+</script>
+
+<div
+  class="fixed top-0 right-0 h-full w-[700px] 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)]">
+        <Server class="w-6 h-6" />
+      </div>
+      <div>
+        <h2 class="text-lg font-semibold text-[var(--text-primary)]">MCP Server Management</h2>
+        <p class="text-xs text-[var(--text-secondary)]">
+          {servers.length} server{servers.length !== 1 ? "s" : ""} configured
+        </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 MCP 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>
+
+  <!-- Add Server Button -->
+  <div class="p-4 border-b border-[var(--border-color)]">
+    <button
+      onclick={() => (showAddForm = !showAddForm)}
+      class="w-full px-4 py-2 bg-[var(--accent-primary)] text-white rounded-lg text-sm font-medium hover:opacity-80 transition-opacity flex items-center justify-center gap-2"
+    >
+      <Server class="w-4 h-4" />
+      {showAddForm ? "Cancel" : "Add New Server"}
+    </button>
+  </div>
+
+  <!-- Add Server Form -->
+  {#if showAddForm}
+    <div
+      class="mx-4 mt-4 p-4 bg-[var(--bg-secondary)]/50 border border-[var(--border-color)] rounded-lg"
+    >
+      <h3 class="text-sm font-medium text-[var(--text-primary)] mb-3">Add MCP Server</h3>
+      <div class="space-y-3">
+        <div>
+          <label class="text-xs text-[var(--text-secondary)] uppercase tracking-wider block mb-1"
+            >Server Name</label
+          >
+          <input
+            type="text"
+            bind:value={newServerName}
+            placeholder="my-server"
+            class="w-full px-3 py-2 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-lg text-[var(--text-primary)] text-sm focus:outline-none focus:border-[var(--accent-primary)]"
+          />
+        </div>
+        <div>
+          <label class="text-xs text-[var(--text-secondary)] uppercase tracking-wider block mb-1"
+            >Transport</label
+          >
+          <select
+            bind:value={newServerTransport}
+            class="w-full px-3 py-2 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-lg text-[var(--text-primary)] text-sm focus:outline-none focus:border-[var(--accent-primary)]"
+          >
+            <option value="stdio">STDIO</option>
+            <option value="http">HTTP</option>
+            <option value="sse">SSE</option>
+          </select>
+        </div>
+        <div>
+          <label class="text-xs text-[var(--text-secondary)] uppercase tracking-wider block mb-1">
+            {newServerTransport === "stdio" ? "Command" : "URL"}
+          </label>
+          <input
+            type="text"
+            bind:value={newServerUrl}
+            placeholder={newServerTransport === "stdio"
+              ? "npx my-mcp-server"
+              : "https://mcp.example.com"}
+            class="w-full px-3 py-2 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-lg text-[var(--text-primary)] text-sm focus:outline-none focus:border-[var(--accent-primary)]"
+          />
+        </div>
+        <button
+          onclick={addServer}
+          disabled={isAdding || !newServerName.trim() || !newServerUrl.trim()}
+          class="w-full 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 justify-center gap-2"
+        >
+          {#if isAdding}
+            <RefreshCw class="w-4 h-4 animate-spin" />
+          {:else}
+            <Server class="w-4 h-4" />
+          {/if}
+          Add Server
+        </button>
+      </div>
+    </div>
+  {/if}
+
+  <!-- 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}
+
+  <!-- Content -->
+  <div class="flex-1 overflow-y-auto p-4 flex gap-4">
+    <!-- Server List -->
+    <div class="flex-1">
+      {#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 servers.length === 0}
+        <div class="flex flex-col items-center justify-center h-full text-[var(--text-secondary)]">
+          <Server class="w-16 h-16 mb-4 opacity-50" />
+          <p class="text-center">No MCP servers configured</p>
+          <p class="text-sm text-center mt-2">Add servers via Settings</p>
+        </div>
+      {:else}
+        <div class="space-y-2">
+          {#each servers as server (server.name)}
+            <button
+              onclick={() => loadServerDetails(server.name)}
+              class="w-full bg-[var(--bg-secondary)]/50 rounded-lg p-3 border border-[var(--border-color)] hover:border-[var(--accent-primary)]/50 transition-all text-left"
+              class:border-[var(--accent-primary)]={selectedServer?.name === server.name}
+            >
+              <div class="flex items-start justify-between">
+                <div class="flex-1">
+                  <h4 class="font-medium text-[var(--text-primary)] flex items-center gap-2">
+                    <svelte:component
+                      this={getTransportIcon(server.transport)}
+                      class="w-4 h-4 {getTransportColor(server.transport)}"
+                    />
+                    {server.name}
+                    {#if server.status}
+                      {#if server.status.includes("Connected")}
+                        <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"
+                        >
+                          ✓
+                        </span>
+                      {:else}
+                        <span
+                          class="px-2 py-0.5 bg-red-500/20 text-red-400 text-xs rounded border border-red-500/30"
+                        >
+                          ✗
+                        </span>
+                      {/if}
+                    {/if}
+                  </h4>
+                  <p class="text-xs text-[var(--text-secondary)] mt-1">
+                    {server.transport.toUpperCase()}
+                    {#if server.url}
+                      • {server.url}
+                    {:else if server.command}
+                      • {server.command}
+                    {/if}
+                  </p>
+                </div>
+              </div>
+            </button>
+          {/each}
+        </div>
+      {/if}
+    </div>
+
+    <!-- Server Details Panel -->
+    {#if selectedServer}
+      <div
+        class="w-80 bg-[var(--bg-secondary)]/50 rounded-lg p-4 border border-[var(--border-color)]"
+      >
+        <h3 class="text-lg font-semibold text-[var(--text-primary)] mb-4">Server Details</h3>
+
+        {#if isLoadingDetails}
+          <div class="flex items-center justify-center h-32">
+            <RefreshCw class="w-6 h-6 animate-spin text-[var(--text-secondary)]" />
+          </div>
+        {:else}
+          <div class="space-y-4">
+            <!-- Name -->
+            <div>
+              <label class="text-xs text-[var(--text-secondary)] uppercase tracking-wider"
+                >Name</label
+              >
+              <p class="text-sm text-[var(--text-primary)] mt-1">{selectedServer.name}</p>
+            </div>
+
+            <!-- Transport -->
+            <div>
+              <label class="text-xs text-[var(--text-secondary)] uppercase tracking-wider"
+                >Transport</label
+              >
+              <p class="text-sm text-[var(--text-primary)] mt-1 flex items-center gap-2">
+                <svelte:component
+                  this={getTransportIcon(selectedServer.transport)}
+                  class="w-4 h-4 {getTransportColor(selectedServer.transport)}"
+                />
+                {selectedServer.transport.toUpperCase()}
+              </p>
+            </div>
+
+            <!-- URL or Command -->
+            {#if selectedServer.url}
+              <div>
+                <label class="text-xs text-[var(--text-secondary)] uppercase tracking-wider"
+                  >URL</label
+                >
+                <p
+                  class="text-sm text-[var(--text-primary)] mt-1 break-all font-mono bg-[var(--bg-primary)] p-2 rounded border border-[var(--border-color)]"
+                >
+                  {selectedServer.url}
+                </p>
+              </div>
+            {/if}
+
+            {#if selectedServer.command}
+              <div>
+                <label class="text-xs text-[var(--text-secondary)] uppercase tracking-wider"
+                  >Command</label
+                >
+                <p
+                  class="text-sm text-[var(--text-primary)] mt-1 font-mono bg-[var(--bg-primary)] p-2 rounded border border-[var(--border-color)]"
+                >
+                  {selectedServer.command}
+                </p>
+              </div>
+            {/if}
+
+            <!-- Environment Variables -->
+            {#if selectedServer.env}
+              <div>
+                <label class="text-xs text-[var(--text-secondary)] uppercase tracking-wider"
+                  >Environment</label
+                >
+                <pre
+                  class="text-xs text-[var(--text-primary)] mt-1 font-mono bg-[var(--bg-primary)] p-2 rounded border border-[var(--border-color)] overflow-x-auto">{JSON.stringify(
+                    selectedServer.env,
+                    null,
+                    2
+                  )}</pre>
+              </div>
+            {/if}
+
+            <!-- Full Server Details -->
+            {#if serverDetails}
+              <div>
+                <label class="text-xs text-[var(--text-secondary)] uppercase tracking-wider"
+                  >Full Details</label
+                >
+                <pre
+                  class="text-xs text-[var(--text-primary)] mt-1 font-mono bg-[var(--bg-primary)] p-2 rounded border border-[var(--border-color)] overflow-x-auto whitespace-pre-wrap">{serverDetails}</pre>
+              </div>
+            {/if}
+
+            <!-- Actions -->
+            <div class="pt-4 border-t border-[var(--border-color)]">
+              <button
+                onclick={() => selectedServer && removeServer(selectedServer.name)}
+                disabled={actionInProgress === selectedServer?.name}
+                class="w-full px-4 py-2 bg-red-500/20 border border-red-500/30 rounded-lg text-sm text-red-400 hover:bg-red-500/30 transition-colors disabled:opacity-40 disabled:cursor-not-allowed flex items-center justify-center gap-2"
+              >
+                <Trash2 class="w-4 h-4" />
+                Remove Server
+              </button>
+            </div>
+          </div>
+        {/if}
+      </div>
+    {/if}
+  </div>
+</div>
+
+<style>
+  @keyframes spin {
+    from {
+      transform: rotate(0deg);
+    }
+    to {
+      transform: rotate(360deg);
+    }
+  }
+
+  .animate-spin {
+    animation: spin 1s linear infinite;
+  }
+</style>