feat: 定时任务调度功能

- 新增 platform_scheduled_tasks 和 platform_task_logs 数据表
- 实现 APScheduler 调度器服务（支持简单模式和CRON表达式）
- 添加定时任务 CRUD API
- 支持手动触发执行和查看执行日志
- 前端任务管理页面

backend/app/main.py

@@ -15,8 +15,10 @@ from .routers.alerts import router as alerts_router
 from .routers.cost import router as cost_router
 from .routers.quota import router as quota_router
 from .routers.tool_configs import router as tool_configs_router
+from .routers.tasks import router as tasks_router
 from .middleware import TraceMiddleware, setup_exception_handlers, RequestLoggerMiddleware
 from .middleware.trace import setup_logging
+from .services.scheduler import start_scheduler, shutdown_scheduler
 
 # 配置日志（包含 TraceID）
 setup_logging(level=logging.INFO, include_trace=True)
@@ -68,6 +70,27 @@ app.include_router(alerts_router, prefix="/api")
 app.include_router(cost_router, prefix="/api")
 app.include_router(quota_router, prefix="/api")
 app.include_router(tool_configs_router, prefix="/api")
+app.include_router(tasks_router, prefix="/api")
+
+
+@app.on_event("startup")
+async def startup_event():
+    """应用启动时初始化调度器"""
+    try:
+        start_scheduler()
+        logging.info("Scheduler started successfully")
+    except Exception as e:
+        logging.error(f"Failed to start scheduler: {e}")
+
+
+@app.on_event("shutdown")
+async def shutdown_event():
+    """应用关闭时停止调度器"""
+    try:
+        shutdown_scheduler()
+        logging.info("Scheduler shutdown successfully")
+    except Exception as e:
+        logging.error(f"Failed to shutdown scheduler: {e}")
 
 
 @app.get("/")