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/frontend/src/components/layout/Sidebar.tsx

@@ -27,6 +27,7 @@ import {
   Users,
   FileSearch,
   ScrollText,
+  Clock,
 } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import { Button } from '@/components/ui/Button';
@@ -78,6 +79,7 @@ const navGroupDefinitions: NavGroupDef[] = [
     items: [
       { path: '/sessions', labelKey: 'navigation.main.sessions', icon: FolderKanban },
       { path: '/lite-tasks', labelKey: 'navigation.main.liteTasks', icon: Zap },
+      { path: '/history', labelKey: 'navigation.main.history', icon: Clock },
       { path: '/issues', labelKey: 'navigation.main.issues', icon: AlertCircle },
       { path: '/analysis', labelKey: 'navigation.main.analysis', icon: FileSearch },
       { path: '/teams', labelKey: 'navigation.main.teams', icon: Users },