Preserve ledger venue provenance (#39)

* feat: preserve ledger venue provenance

* fix: satisfy ledger test lint ratchet

* fix: advance image migration inventory

app/repositories/portfolio_repository.py

@@ -9,6 +9,10 @@ from typing import Protocol
 from app.domain.models import Asset, AuthToken, BrokerCredential, CorporateAction, Daemon, LedgerEntry, Portfolio, PortfolioComment, PortfolioTag, StrategySet, Tag, TokenPrincipal, User
 
 
+class LedgerTradeConflictError(ValueError):
+    """A duplicate broker-ledger key disagrees with its persisted payload."""
+
+
 class PortfolioRepository(Protocol):
     def ping(self) -> None: ...
 
@@ -324,6 +328,8 @@ class PortfolioRepository(Protocol):
         executed_at: datetime,
         fee_amount: float = 0.0,
         tax_amount: float = 0.0,
+        execution_venue: str | None = None,
+        order_venue: str | None = None,
     ) -> tuple[LedgerEntry, bool]: ...
 
     def record_manual_ledger(