feat(queue): implement queue scheduler service and API routes

- Added QueueSchedulerService to manage task queue lifecycle, including state machine, dependency resolution, and session management.
- Implemented HTTP API endpoints for queue scheduling:
  - POST /api/queue/execute: Submit items to the scheduler.
  - GET /api/queue/scheduler/state: Retrieve full scheduler state.
  - POST /api/queue/scheduler/start: Start scheduling loop with items.
  - POST /api/queue/scheduler/pause: Pause scheduling.
  - POST /api/queue/scheduler/stop: Graceful stop of the scheduler.
  - POST /api/queue/scheduler/config: Update scheduler configuration.
- Introduced types for queue items, scheduler state, and WebSocket messages to ensure type safety and compatibility with the backend.
- Added static model lists for LiteLLM as a fallback for available models.

ccw/src/tools/native-session-discovery.ts

@@ -1197,3 +1197,30 @@ export function getToolSessionPath(tool: string): string | null {
   const discoverer = discoverers[tool];
   return discoverer?.basePath || null;
 }
+
+/**
+ * List all native sessions from all supported CLI tools
+ * Aggregates sessions from Gemini, Qwen, Codex, Claude, and OpenCode
+ * @param options - Optional filtering (workingDir, limit, afterTimestamp)
+ * @returns Combined sessions sorted by updatedAt descending
+ */
+export function listAllNativeSessions(options?: SessionDiscoveryOptions): NativeSession[] {
+  const allSessions: NativeSession[] = [];
+
+  // Collect sessions from all discoverers
+  for (const tool of Object.keys(discoverers)) {
+    const discoverer = discoverers[tool];
+    const sessions = discoverer.getSessions(options);
+    allSessions.push(...sessions);
+  }
+
+  // Sort by updatedAt descending
+  allSessions.sort((a, b) => b.updatedAt.getTime() - a.updatedAt.getTime());
+
+  // Apply limit if provided
+  if (options?.limit) {
+    return allSessions.slice(0, options.limit);
+  }
+
+  return allSessions;
+}