feat: v0.12.0 — fix streaming tool UI persistence, file tree UX improvements, unify icon library

Streaming tool UI fix (ChatView.tsx):
- Add toolUsesRef/toolResultsRef to reliably track tool data across closures
- Serialize tool_use/tool_result into JSON content-blocks array when building
  assistant message after stream ends, matching backend storage format
- MessageItem.parseToolBlocks() now renders tool UI from history messages
- Clean up refs in finally block and timeout auto-retry path

File tree UX (FileTree.tsx, file-tree.tsx):
- Remove folder path header from right panel, merge search + refresh into one row
- Remove file icon spacer (size-5) so file icons align flush with search box
- Change folder icon color from blue to muted-foreground

Chat list panel (ChatListPanel.tsx):
- Folder header: expanded uses FolderOpenIcon, collapsed uses Folder01Icon
- Add tooltip showing full working directory path on folder hover
- Double-click folder header opens in system file manager

Title bar folder name (chat/[id]/page.tsx):
- Add tooltip with full path on project name hover
- Click opens folder in Finder/Explorer via Electron IPC or API fallback

Open folder support:
- electron/main.ts: add shell:open-path IPC handler via shell.openPath
- electron/preload.ts: expose electronAPI.shell.openPath to renderer
- api/files/open/route.ts: fallback API route using open/explorer/xdg-open

Unify icon library — migrate app-level components from Lucide to Hugeicons:
- file-tree.tsx: folder, file, chevron, plus icons
- tool-actions-group.tsx: chevron expand icon
- MessageItem.tsx: copy, check, expand/collapse icons
- MessageInput.tsx: stop button (SquareIcon → StopIcon)
- FileCard.tsx: file icon
- ImageLightbox.tsx: left/right navigation arrows
- InstallWizard.tsx: status icons (check, x, minus, loader, circle, copy, download)
- Keep Lucide in ui/ and ai-elements/ base layers (shadcn standard)

src/app/api/chat/mode/route.ts

@@ -0,0 +1,29 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getConversation } from '@/lib/conversation-registry';
+import type { PermissionMode } from '@anthropic-ai/claude-agent-sdk';
+
+export const runtime = 'nodejs';
+export const dynamic = 'force-dynamic';
+
+export async function POST(request: NextRequest) {
+  try {
+    const { sessionId, mode } = await request.json();
+
+    if (!sessionId || !mode) {
+      return NextResponse.json({ error: 'sessionId and mode are required' }, { status: 400 });
+    }
+
+    const conversation = getConversation(sessionId);
+    if (!conversation) {
+      return NextResponse.json({ applied: false });
+    }
+
+    const permissionMode: PermissionMode = mode === 'code' ? 'acceptEdits' : 'plan';
+    await conversation.setPermissionMode(permissionMode);
+
+    return NextResponse.json({ applied: true });
+  } catch (error) {
+    console.error('[mode] Failed to switch mode:', error);
+    return NextResponse.json({ applied: false, error: String(error) });
+  }
+}

src/app/api/chat/permission/route.ts

@@ -23,6 +23,7 @@ export async function POST(request: NextRequest) {
       result = {
         behavior: 'allow',
         updatedPermissions: decision.updatedPermissions as unknown as PermissionUpdate[],
+        ...(decision.updatedInput ? { updatedInput: decision.updatedInput } : {}),
       };
     } else {
       result = {