fix: add missing postgres implementations for get_portfolio_by_name_and_user and insert_ledger_trade

- add get_portfolio_by_name_and_user to PortfolioRepository protocol and
  PostgresPortfolioRepository; resolves AttributeError on all CLI name+user
  resolution paths (REQ-017)
- add insert_ledger_trade to PortfolioRepository protocol and
  PostgresPortfolioRepository; resolves HTTP 500 on POST
  /v1/assets/{asset_id}/ledger/trades (REQ-008)
- add _row_to_ledger_trade static helper; uses INSERT ... ON CONFLICT DO
  NOTHING RETURNING to return (LedgerTrade, created: bool)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/repositories/portfolio_repository.py

@@ -5,7 +5,7 @@ from __future__ import annotations
 from datetime import datetime
 from typing import Protocol
 
-from app.domain.models import AuthToken, BrokerCredential, Daemon, LedgerEntry, Portfolio, PortfolioComment, PortfolioTag, StrategySet, TokenPrincipal, User
+from app.domain.models import AuthToken, BrokerCredential, Daemon, LedgerEntry, LedgerTrade, Portfolio, PortfolioComment, PortfolioTag, StrategySet, TokenPrincipal, User
 
 
 class PortfolioRepository(Protocol):
@@ -198,6 +198,20 @@ class PortfolioRepository(Protocol):
 
     def list_recent_trades(self, portfolio_id: str, limit: int = 5) -> list[LedgerEntry]: ...
 
+    def insert_ledger_trade(
+        self,
+        *,
+        asset_id: str,
+        order_id: str,
+        execution_id: str,
+        side: str,
+        quantity: float,
+        price: float,
+        executed_at: datetime,
+        fee_amount: float = 0.0,
+        tax_amount: float = 0.0,
+    ) -> tuple[LedgerTrade, bool]: ...
+
     def reset(self, portfolio_id: str) -> Portfolio: ...
 
     def adjust_buffer(self, portfolio_id: str, amount: float, action: str, note: str = "") -> Portfolio: ...