feat: persist probe quality and notification outbox

backend/app/models/notification_outbox.py

@@ -0,0 +1,55 @@
+"""Durable delivery queue for alert notifications."""
+
+import enum
+from datetime import datetime
+
+from sqlalchemy import BigInteger, Column, DateTime, Enum, Index, Integer, String, Text
+
+from .device import Base
+
+
+PRIMARY_KEY_TYPE = BigInteger().with_variant(Integer, "sqlite")
+
+
+class NotificationStatus(str, enum.Enum):
+    """Lifecycle states for a notification delivery attempt."""
+
+    pending = "pending"
+    sending = "sending"
+    sent = "sent"
+    failed = "failed"
+
+
+class NotificationOutbox(Base):
+    """A notification retained until a dispatcher records its final outcome."""
+
+    __tablename__ = "notification_outbox"
+
+    id = Column(PRIMARY_KEY_TYPE, primary_key=True, autoincrement=True)
+    alert_event_id = Column(BigInteger, nullable=False, index=True, comment="关联告警事件 ID")
+    message_content = Column(Text, nullable=False, comment="待发送的脱敏消息摘要")
+    delivery_scope = Column(String(256), nullable=True, comment="受控投递范围摘要")
+    status = Column(
+        Enum(NotificationStatus),
+        nullable=False,
+        default=NotificationStatus.pending,
+        server_default=NotificationStatus.pending.value,
+        comment="投递状态",
+    )
+    attempt_count = Column(Integer, nullable=False, default=0, comment="投递尝试次数")
+    next_attempt_at = Column(DateTime, nullable=True, comment="下次允许投递时间")
+    locked_at = Column(DateTime, nullable=True, comment="投递器领取时间")
+    sent_at = Column(DateTime, nullable=True, comment="成功投递时间")
+    last_error = Column(String(512), nullable=True, comment="最近一次投递错误摘要")
+    created_at = Column(DateTime, default=datetime.now, nullable=False, comment="创建时间")
+    updated_at = Column(
+        DateTime,
+        default=datetime.now,
+        onupdate=datetime.now,
+        nullable=False,
+        comment="更新时间",
+    )
+
+    __table_args__ = (
+        Index("idx_notification_outbox_status_next_attempt", "status", "next_attempt_at"),
+    )