fix: 修复定时任务模型字段与数据库表不匹配的问题

- task_type -> execution_type
- status -> is_enabled
- 移除不存在的字段 webhook_method, webhook_headers, script_timeout
- time_points/input_params 适配 JSON 类型

backend/app/models/scheduled_task.py

@@ -1,6 +1,6 @@
 """定时任务相关模型"""
 from datetime import datetime
-from sqlalchemy import Column, BigInteger, Integer, String, Text, Enum, SmallInteger, TIMESTAMP, DateTime
+from sqlalchemy import Column, BigInteger, Integer, String, Text, Enum, SmallInteger, TIMESTAMP, DateTime, JSON, Boolean
 from ..database import Base
 
 
@@ -11,40 +11,43 @@ class ScheduledTask(Base):
     id = Column(Integer, primary_key=True, autoincrement=True)
     tenant_id = Column(String(50))
     task_name = Column(String(100), nullable=False)
-    task_type = Column(Enum('webhook', 'script'), nullable=False, default='script')
+    task_desc = Column(String(500))
     
     # 调度配置
     schedule_type = Column(Enum('simple', 'cron'), nullable=False, default='simple')
-    time_points = Column(Text)  # JSON数组 ["08:00", "12:00"]
+    time_points = Column(JSON)  # JSON数组 ["08:00", "12:00"]
     cron_expression = Column(String(100))
+    timezone = Column(String(50), default='Asia/Shanghai')
+    
+    # 执行类型
+    execution_type = Column(Enum('webhook', 'script'), nullable=False, default='script')
     
     # Webhook配置
     webhook_url = Column(String(500))
-    webhook_method = Column(String(10), default='POST')
-    webhook_headers = Column(Text)  # JSON格式
     
     # 脚本配置
     script_content = Column(Text)
-    script_timeout = Column(Integer, default=300)
+    script_deps = Column(Text)  # 脚本依赖
     
     # 输入参数
-    input_params = Column(Text)  # JSON格式
+    input_params = Column(JSON)  # JSON格式
     
     # 重试配置
     retry_count = Column(Integer, default=0)
     retry_interval = Column(Integer, default=60)
     
     # 告警配置
-    alert_on_failure = Column(SmallInteger, default=0)
+    alert_on_failure = Column(Boolean, default=False)
     alert_webhook = Column(String(500))
     
     # 状态
-    status = Column(SmallInteger, default=1)  # 0-禁用 1-启用
+    is_enabled = Column(Boolean, default=True)
     last_run_at = Column(DateTime)
-    last_run_status = Column(String(20))
+    last_run_status = Column(Enum('success', 'failed', 'running'))
+    last_run_message = Column(Text)
     
-    created_at = Column(TIMESTAMP, default=datetime.now)
-    updated_at = Column(TIMESTAMP, default=datetime.now, onupdate=datetime.now)
+    created_at = Column(DateTime, default=datetime.now)
+    updated_at = Column(DateTime, default=datetime.now, onupdate=datetime.now)
 
 
 class TaskLog(Base):