feat: persist probe quality and notification outbox

backend/app/models/alert_event.py

@@ -1,11 +1,15 @@
 import enum
 from datetime import datetime
-from sqlalchemy import Column, Integer, String, Boolean, DateTime, BigInteger, Enum
+from sqlalchemy import BigInteger, Boolean, Column, DateTime, Enum, Integer, String
 from .device import Base
 
 
+PRIMARY_KEY_TYPE = BigInteger().with_variant(Integer, "sqlite")
+
+
 class AlertTypeEnum(str, enum.Enum):
     offline = "offline"           # 设备离线
+    degraded = "degraded"         # 设备丢包故障
     recovered = "recovered"       # 设备恢复
     system = "system"             # 系统告警（如上游断网检测）
 
@@ -14,7 +18,7 @@ class AlertEvent(Base):
     """告警事件表"""
     __tablename__ = "alert_events"
 
-    id = Column(BigInteger, primary_key=True, autoincrement=True)
+    id = Column(PRIMARY_KEY_TYPE, primary_key=True, autoincrement=True)
     device_id = Column(Integer, nullable=False, index=True, comment="关联设备 ID")
     alert_type = Column(Enum(AlertTypeEnum), nullable=False, comment="告警类型")
     message = Column(String(1024), default="", comment="告警消息摘要")
@@ -26,6 +30,14 @@ class AlertEvent(Base):
 
     is_resolved = Column(Boolean, default=False, comment="是否已恢复")
     notification_sent = Column(Boolean, default=False, comment="是否已发送通知")
+    notification_attempts = Column(Integer, default=0, comment="通知尝试次数")
+    last_notification_error = Column(
+        String(512),
+        nullable=True,
+        comment="最近一次通知失败原因",
+    )
+    previous_status = Column(String(16), nullable=True, comment="状态变更前状态")
+    current_status = Column(String(16), nullable=True, comment="状态变更后状态")
     acknowledged_at = Column(DateTime, nullable=True, comment="用户确认时间")
 
     created_at = Column(DateTime, default=datetime.now, comment="创建时间")