fix: enforce snapshot-consistent precision checks for manual ledger

Co-authored-by: genichin <4282227+genichin@users.noreply.github.com>

tests/test_v1_portfolios_manual_ledger.py

@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from contextlib import ExitStack
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from typing import Any
 from unittest.mock import patch
 
@@ -195,7 +195,7 @@ class _FakeRepo:
             fee_amount=fee,
             tax_amount=tax,
             executed_at=executed_at,
-            recorded_at=datetime.now(timezone.utc),
+            recorded_at=datetime.now(UTC),
             cash_balance_after=self.portfolio.cash_balance,
             asset_quantity_after=self.portfolio.asset_quantity,
             profit_buffer_after=self.portfolio.profit_buffer,
@@ -674,7 +674,7 @@ def test_unified_ledger_paginates_mixed_sources_and_hides_side() -> None:
     repo.entries.append(
         LedgerEntry(
             ledger_entry_id=99, portfolio_id=_PORTFOLIO_ID, side="buy", quantity=2, price=10, source="broker",
-            recorded_at=datetime.now(timezone.utc), cash_balance_after=900, asset_quantity_after=12,
+            recorded_at=datetime.now(UTC), cash_balance_after=900, asset_quantity_after=12,
         )
     )
     first = client.get(f"/v1/portfolios/{_PORTFOLIO_ID}/ledger?limit=1", headers=_auth())