fix(ledger): keep legacy amount wire type and preserve dividend tax decimals

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

app/repositories/postgres.py

@@ -703,6 +703,7 @@ class PostgresPortfolioRepository:
 
     @staticmethod
     def _row_to_ledger_entry_legacy(row: Any) -> LedgerEntry:
+        raw_tax = row[6]
         return LedgerEntry(
             ledger_entry_id=0,
             portfolio_id=row[0],
@@ -713,7 +714,8 @@ class PostgresPortfolioRepository:
             price=float(row[3]),
             price_decimal=Decimal(str(row[3])) if row[3] is not None else None,
             fee_amount=float(row[5]),
-            tax_amount=float(row[6]),
+            tax_amount=float(raw_tax),
+            tax_amount_decimal=Decimal(str(raw_tax)) if raw_tax is not None else None,
             executed_at=row[1],
             recorded_at=row[1],
             cash_balance_after=float(row[7]),
@@ -1866,6 +1868,7 @@ class PostgresPortfolioRepository:
         if row is None:
             raise ValueError("원장 항목을 찾을 수 없습니다")
         raw_price = row[6]
+        raw_tax = row[8]
         return LedgerEntry(
             ledger_entry_id=int(row[0]),
             portfolio_id=row[1],
@@ -1876,7 +1879,8 @@ class PostgresPortfolioRepository:
             price=float(raw_price),
             price_decimal=Decimal(str(raw_price)) if raw_price is not None else None,
             fee_amount=float(row[7]),
-            tax_amount=float(row[8]),
+            tax_amount=float(raw_tax),
+            tax_amount_decimal=Decimal(str(raw_tax)) if raw_tax is not None else None,
             executed_at=row[9],
             recorded_at=row[10],
             cash_balance_after=float(row[11]),