feat: add built-in file editor with syntax highlighting

- Add CodeMirror 6 editor with support for 40+ languages
- Add file browser sidebar with directory tree navigation
- Add multi-tab support with dirty state indicators
- Add keyboard shortcuts (Ctrl+E, Ctrl+B, Ctrl+S, Ctrl+W)
- Add editor toggle button to status bar
- Editor uses current session's CWD and requires connection
- Add Tauri commands for file operations (list, read, write)

src/routes/+page.svelte

@@ -7,6 +7,7 @@
   import { initNotificationSync, cleanupNotificationSync } from "$lib/stores/notifications";
   import { conversationsStore } from "$lib/stores/conversations";
   import { claudeStore, isClaudeProcessing } from "$lib/stores/claude";
+  import { editorStore } from "$lib/stores/editor";
   import { getCurrentWindow, LogicalSize } from "@tauri-apps/api/window";
   import "$lib/notifications/testNotifications";
   import Terminal from "$lib/components/Terminal.svelte";
@@ -14,6 +15,7 @@
   import StatusBar from "$lib/components/StatusBar.svelte";
   import AnimeGirl from "$lib/components/AnimeGirl.svelte";
   import CompactMode from "$lib/components/CompactMode.svelte";
+  import EditorPanel from "$lib/components/editor/EditorPanel.svelte";
   import { characterState } from "$lib/stores/character";
   import type { CharacterState } from "$lib/types/states";
   import PermissionModal from "$lib/components/PermissionModal.svelte";
@@ -29,6 +31,32 @@
   let currentCharacterState: CharacterState = $state("idle");
   let compactModeActive = $state(false);
 
+  // Editor state
+  const isEditorVisible = editorStore.isEditorVisible;
+  let lastInitializedCwd = "";
+
+  // Track connection status and CWD for the editor
+  const connectionStatus = claudeStore.connectionStatus;
+  const currentWorkingDirectory = claudeStore.currentWorkingDirectory;
+
+  // Initialize/update editor file tree when CWD changes while editor is visible
+  $effect(() => {
+    const visible = $isEditorVisible;
+    const cwd = $currentWorkingDirectory;
+    const connected = $connectionStatus === "connected";
+
+    // Only initialize when editor is visible, connected, and CWD is set
+    if (visible && connected && cwd && cwd !== lastInitializedCwd) {
+      lastInitializedCwd = cwd;
+      editorStore.initializeFileTree(cwd);
+    }
+
+    // Hide editor if disconnected
+    if (!connected && visible) {
+      editorStore.hideEditor();
+    }
+  });
+
   // Window size constants
   const COMPACT_WIDTH = 280;
   const COMPACT_HEIGHT = 400;
@@ -176,6 +204,40 @@
       toggleCompactMode();
       return;
     }
+
+    // Ctrl+E - Toggle editor panel (only when connected)
+    if (event.ctrlKey && event.key === "e") {
+      event.preventDefault();
+      // Only allow opening the editor when connected
+      if (get(claudeStore.connectionStatus) === "connected") {
+        editorStore.toggleEditor();
+      }
+      return;
+    }
+
+    // Ctrl+B - Toggle file browser (when editor is visible)
+    if (event.ctrlKey && event.key === "b" && get(editorStore.isEditorVisible)) {
+      event.preventDefault();
+      editorStore.toggleFileBrowser();
+      return;
+    }
+
+    // Ctrl+S - Save current file (when editor is visible)
+    if (event.ctrlKey && event.key === "s" && get(editorStore.isEditorVisible)) {
+      event.preventDefault();
+      editorStore.saveFile();
+      return;
+    }
+
+    // Ctrl+W - Close current tab (when editor is visible)
+    if (event.ctrlKey && event.key === "w" && get(editorStore.isEditorVisible)) {
+      event.preventDefault();
+      const activeTabId = get(editorStore.activeTabId);
+      if (activeTabId) {
+        editorStore.closeTab(activeTabId);
+      }
+      return;
+    }
   }
 
   async function handleInterrupt() {
@@ -330,10 +392,14 @@
         onmousedown={startResize}
       ></div>
 
-      <!-- Right panel: Terminal and input -->
+      <!-- Right panel: Terminal/Editor and input -->
       <div class="terminal-panel flex-1 flex flex-col min-w-0">
-        <Terminal />
-        <InputBar />
+        {#if $isEditorVisible}
+          <EditorPanel />
+        {:else}
+          <Terminal />
+          <InputBar />
+        {/if}
       </div>
     </main>