feat: 脚本执行平台增强功能

- 新增重试和失败告警功能（支持自动重试N次，失败后钉钉/企微通知）
- 新增密钥管理（安全存储API Key等敏感信息）
- 新增脚本模板库（预置常用脚本模板）
- 新增脚本版本管理（自动保存历史版本，支持回滚）
- 新增执行统计（成功率、平均耗时、7日趋势）
- SDK 新增多租户遍历能力（get_tenants/get_tenant_config/get_all_tenant_configs）
- SDK 新增密钥读取方法（get_secret）

backend/app/services/scheduler.py

@@ -31,10 +31,81 @@ def get_db_session() -> Session:
     return SessionLocal()
 
 
+async def send_alert(webhook: str, task_name: str, error_message: str):
+    """发送失败告警通知"""
+    try:
+        # 自动判断钉钉或企微
+        if "dingtalk" in webhook or "oapi.dingtalk.com" in webhook:
+            data = {
+                "msgtype": "markdown",
+                "markdown": {
+                    "title": "定时任务执行失败",
+                    "text": f"### ⚠️ 定时任务执行失败\n\n**任务名称**：{task_name}\n\n**错误信息**：{error_message[:500]}\n\n**时间**：{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}"
+                }
+            }
+        else:
+            # 企微格式
+            data = {
+                "msgtype": "markdown",
+                "markdown": {
+                    "content": f"### ⚠️ 定时任务执行失败\n\n**任务名称**：{task_name}\n\n**错误信息**：{error_message[:500]}\n\n**时间**：{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}"
+                }
+            }
+        
+        async with httpx.AsyncClient(timeout=30.0) as client:
+            await client.post(webhook, json=data)
+        logger.info(f"Alert sent for task {task_name}")
+    except Exception as e:
+        logger.warning(f"Failed to send alert: {e}")
+
+
+async def execute_task_with_retry(task_id: int, retry_count: int = 0, max_retries: int = 0, retry_interval: int = 60):
+    """带重试的任务执行"""
+    success = await execute_task_once(task_id)
+    
+    if not success and retry_count < max_retries:
+        logger.info(f"Task {task_id} failed, scheduling retry {retry_count + 1}/{max_retries} in {retry_interval}s")
+        await asyncio.sleep(retry_interval)
+        await execute_task_with_retry(task_id, retry_count + 1, max_retries, retry_interval)
+    elif not success:
+        # 所有重试都失败，发送告警
+        db = get_db_session()
+        try:
+            result = db.execute(
+                text("SELECT task_name, alert_on_failure, alert_webhook, last_run_message FROM platform_scheduled_tasks WHERE id = :id"),
+                {"id": task_id}
+            )
+            task = result.mappings().first()
+            if task and task["alert_on_failure"] and task["alert_webhook"]:
+                await send_alert(task["alert_webhook"], task["task_name"], task["last_run_message"] or "未知错误")
+        finally:
+            db.close()
+
+
 async def execute_task(task_id: int):
-    """执行定时任务"""
+    """执行定时任务入口（处理重试配置）"""
+    db = get_db_session()
+    try:
+        result = db.execute(
+            text("SELECT retry_count, retry_interval FROM platform_scheduled_tasks WHERE id = :id"),
+            {"id": task_id}
+        )
+        task = result.mappings().first()
+        if task:
+            max_retries = task.get("retry_count", 0) or 0
+            retry_interval = task.get("retry_interval", 60) or 60
+            await execute_task_with_retry(task_id, 0, max_retries, retry_interval)
+        else:
+            await execute_task_once(task_id)
+    finally:
+        db.close()
+
+
+async def execute_task_once(task_id: int) -> bool:
+    """执行一次定时任务，返回是否成功"""
     db = get_db_session()
     log_id = None
+    success = False
     
     try:
         # 1. 查询任务配置
@@ -46,7 +117,7 @@ async def execute_task(task_id: int):
         
         if not task:
             logger.warning(f"Task {task_id} not found or disabled")
-            return
+            return True  # 不需要重试
         
         # 2. 更新任务状态为运行中
         db.execute(
@@ -161,9 +232,11 @@ async def execute_task(task_id: int):
         db.commit()
         
         logger.info(f"Task {task_id} executed with status: {status}")
+        success = (status == "success")
         
     except Exception as e:
         logger.error(f"Task {task_id} execution error: {str(e)}")
+        success = False
         
         # 更新失败状态
         try:
@@ -190,6 +263,8 @@ async def execute_task(task_id: int):
             pass
     finally:
         db.close()
+    
+    return success
 
 
 def add_task_to_scheduler(task: Dict[str, Any]):