feat(portfolio): add atomic corporate action persistence

app/domain/models.py

@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass, field
-from datetime import datetime
+from datetime import date, datetime
 from decimal import Decimal
 from enum import Enum
 from typing import Any, Protocol, runtime_checkable
@@ -132,6 +132,29 @@ class Portfolio:
     managed_by_daemon_id: str | None = None
 
 
+@dataclass
+class CorporateAction:
+    corporate_action_id: str
+    portfolio_id: str
+    asset_id: str | None
+    action_type: str
+    effective_date: date
+    quantity_before: Decimal
+    quantity_after: Decimal
+    average_price_before: Decimal
+    average_price_after: Decimal
+    total_cost_basis: Decimal
+    cash_balance: Decimal
+    profit_buffer: Decimal
+    evidence_ref: str
+    idempotency_key: str
+    payload_hash: str
+    ledger_entry_id: int
+    actor_user_id: str | None = None
+    recorded_at: datetime | None = None
+    idempotent_replay: bool = False
+
+
 @dataclass
 class LedgerEntry:
     portfolio_id: str