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/http-api-client.ts

@@ -510,7 +510,53 @@ type EventType =
   | 'ideation:analysis'
   | 'worktree:init-started'
   | 'worktree:init-output'
-  | 'worktree:init-completed';
+  | 'worktree:init-completed'
+  | 'dev-server:started'
+  | 'dev-server:output'
+  | 'dev-server:stopped';
+
+/**
+ * Dev server log event payloads for WebSocket streaming
+ */
+export interface DevServerStartedEvent {
+  worktreePath: string;
+  port: number;
+  url: string;
+  timestamp: string;
+}
+
+export interface DevServerOutputEvent {
+  worktreePath: string;
+  content: string;
+  timestamp: string;
+}
+
+export interface DevServerStoppedEvent {
+  worktreePath: string;
+  port: number;
+  exitCode: number | null;
+  error?: string;
+  timestamp: string;
+}
+
+export type DevServerLogEvent =
+  | { type: 'dev-server:started'; payload: DevServerStartedEvent }
+  | { type: 'dev-server:output'; payload: DevServerOutputEvent }
+  | { type: 'dev-server:stopped'; payload: DevServerStoppedEvent };
+
+/**
+ * Response type for fetching dev server logs
+ */
+export interface DevServerLogsResponse {
+  success: boolean;
+  result?: {
+    worktreePath: string;
+    port: number;
+    logs: string;
+    startedAt: string;
+  };
+  error?: string;
+}
 
 type EventCallback = (payload: unknown) => void;
 
@@ -1710,6 +1756,24 @@ export class HttpApiClient implements ElectronAPI {
       this.post('/api/worktree/start-dev', { projectPath, worktreePath }),
     stopDevServer: (worktreePath: string) => this.post('/api/worktree/stop-dev', { worktreePath }),
     listDevServers: () => this.post('/api/worktree/list-dev-servers', {}),
+    getDevServerLogs: (worktreePath: string): Promise<DevServerLogsResponse> =>
+      this.get(`/api/worktree/dev-server-logs?worktreePath=${encodeURIComponent(worktreePath)}`),
+    onDevServerLogEvent: (callback: (event: DevServerLogEvent) => void) => {
+      const unsub1 = this.subscribeToEvent('dev-server:started', (payload) =>
+        callback({ type: 'dev-server:started', payload: payload as DevServerStartedEvent })
+      );
+      const unsub2 = this.subscribeToEvent('dev-server:output', (payload) =>
+        callback({ type: 'dev-server:output', payload: payload as DevServerOutputEvent })
+      );
+      const unsub3 = this.subscribeToEvent('dev-server:stopped', (payload) =>
+        callback({ type: 'dev-server:stopped', payload: payload as DevServerStoppedEvent })
+      );
+      return () => {
+        unsub1();
+        unsub2();
+        unsub3();
+      };
+    },
     getPRInfo: (worktreePath: string, branchName: string) =>
       this.post('/api/worktree/pr-info', { worktreePath, branchName }),
     // Init script methods