feat: add dev server log panel with real-time streaming

Add the ability to view dev server logs in a dedicated panel with:
- Real-time log streaming via WebSocket events
- ANSI color support using xterm.js
- Scrollback buffer (50KB) for log history on reconnect
- Output throttling to prevent UI flooding
- "View Logs" option in worktree dropdown menu

Server changes:
- Add scrollback buffer and event emission to DevServerService
- Add GET /api/worktree/dev-server-logs endpoint
- Add dev-server:started, dev-server:output, dev-server:stopped events

UI changes:
- Add reusable XtermLogViewer component
- Add DevServerLogsPanel dialog component
- Add useDevServerLogs hook for WebSocket subscription

Closes #462

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/ui/src/lib/electron.ts

@@ -1760,6 +1760,22 @@ function createMockWorktreeAPI(): WorktreeAPI {
       };
     },
 
+    getDevServerLogs: async (worktreePath: string) => {
+      console.log('[Mock] Getting dev server logs:', { worktreePath });
+      return {
+        success: false,
+        error: 'No dev server running for this worktree',
+      };
+    },
+
+    onDevServerLogEvent: (callback) => {
+      console.log('[Mock] Subscribing to dev server log events');
+      // Return unsubscribe function
+      return () => {
+        console.log('[Mock] Unsubscribing from dev server log events');
+      };
+    },
+
     getPRInfo: async (worktreePath: string, branchName: string) => {
       console.log('[Mock] Getting PR info:', { worktreePath, branchName });
       return {