feat(approval): add safe risk disposition workflow

server/src/app/models/approval_action.py

@@ -0,0 +1,64 @@
+from __future__ import annotations
+
+import uuid
+from datetime import datetime
+from typing import Any
+
+from sqlalchemy import CheckConstraint, DateTime, Index, String, UniqueConstraint, func
+from sqlalchemy.orm import Mapped, mapped_column
+from sqlalchemy.types import JSON
+
+from app.db.base_class import Base
+
+
+class ApprovalActionLedger(Base):
+    """审批类写动作的持久化幂等账本。"""
+
+    __tablename__ = "approval_action_ledgers"
+    __table_args__ = (
+        CheckConstraint(
+            "action IN ('approve', 'return', 'pay')",
+            name="ck_approval_action_ledger_action",
+        ),
+        CheckConstraint(
+            "(completed_at IS NULL AND result_status IS NULL "
+            "AND result_approval_stage IS NULL) OR "
+            "(completed_at IS NOT NULL AND result_status IS NOT NULL "
+            "AND result_approval_stage IS NOT NULL)",
+            name="ck_approval_action_ledger_completion",
+        ),
+        UniqueConstraint(
+            "tenant_id",
+            "actor_id",
+            "request_id",
+            name="uq_approval_action_ledger_request",
+        ),
+        Index(
+            "ix_approval_action_ledger_claim_action",
+            "tenant_id",
+            "claim_id",
+            "action",
+        ),
+    )
+
+    id: Mapped[str] = mapped_column(
+        String(36),
+        primary_key=True,
+        default=lambda: str(uuid.uuid4()),
+    )
+    tenant_id: Mapped[str] = mapped_column(String(64), nullable=False)
+    actor_id: Mapped[str] = mapped_column(String(120), nullable=False)
+    request_id: Mapped[str] = mapped_column(String(120), nullable=False)
+    claim_id: Mapped[str] = mapped_column(String(36), nullable=False)
+    action: Mapped[str] = mapped_column(String(20), nullable=False)
+    payload_fingerprint: Mapped[str] = mapped_column(String(80), nullable=False)
+    expected_status: Mapped[str] = mapped_column(String(30), nullable=False)
+    expected_approval_stage: Mapped[str] = mapped_column(String(50), nullable=False)
+    result_status: Mapped[str | None] = mapped_column(String(30), nullable=True)
+    result_approval_stage: Mapped[str | None] = mapped_column(String(50), nullable=True)
+    response_json: Mapped[dict[str, Any] | None] = mapped_column(JSON, nullable=True)
+    completed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+    )