feat: persist subscription side-effect outbox

app/db/models/outbox.py

@@ -0,0 +1,30 @@
+"""持久副作用 outbox 模型。"""
+
+from typing import Any, Optional
+
+from sqlalchemy import Index, Integer, JSON, String, Text, UniqueConstraint
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.db.base import Base, get_id_column
+
+
+class OutboxMessage(Base):
+    """记录与业务事务原子提交、可认领重试的副作用意图。"""
+
+    id = get_id_column()
+    event_key: Mapped[str] = mapped_column(String(255), nullable=False)
+    topic: Mapped[str] = mapped_column(String(100), nullable=False)
+    payload_version: Mapped[int] = mapped_column(Integer, nullable=False, default=1)
+    payload: Mapped[dict[str, Any]] = mapped_column(JSON, nullable=False)
+    status: Mapped[str] = mapped_column(String(20), nullable=False, default="pending")
+    attempt: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    next_retry_at: Mapped[str] = mapped_column(String(40), nullable=False)
+    lease_until: Mapped[Optional[str]] = mapped_column(String(40))
+    last_error: Mapped[Optional[str]] = mapped_column(Text)
+    created_at: Mapped[str] = mapped_column(String(40), nullable=False)
+    completed_at: Mapped[Optional[str]] = mapped_column(String(40))
+
+    __table_args__ = (
+        UniqueConstraint("event_key", name="uq_outboxmessage_event_key"),
+        Index("ix_outboxmessage_claim", "status", "next_retry_at", "lease_until"),
+    )