fix(portfolio): tolerate consolidation WAC residue

app/repositories/postgres.py

@@ -14,6 +14,7 @@ from typing import Any
 import psycopg
 from psycopg import sql
 
+from app.domain.corporate_actions import calculate_stock_consolidation
 from app.domain.errors import (
     DaemonInactiveError,
     DaemonInUseError,
@@ -1668,11 +1669,14 @@ class PostgresPortfolioRepository:
                 wac = calculate_current_wac(history)
                 if Decimal(str(row[0])) != action.quantity_before or Decimal(str(wac.current_quantity)) != action.quantity_before:
                     raise ValueError("CORPORATE_ACTION_STALE_QUANTITY")
-                action.average_price_before = Decimal(str(wac.current_wac or 0))
-                action.total_cost_basis = (action.average_price_before * action.quantity_before).quantize(Decimal("0.00000001"))
-                action.average_price_after = (action.total_cost_basis / action.quantity_after).quantize(Decimal("0.00000001"))
-                if action.average_price_after * action.quantity_after != action.total_cost_basis:
-                    raise ValueError("FRACTIONAL_RESULT_UNSUPPORTED")
+                consolidation = calculate_stock_consolidation(
+                    action.quantity_before,
+                    action.quantity_after,
+                    Decimal(str(wac.current_wac or 0)),
+                )
+                action.average_price_before = consolidation.average_price_before
+                action.average_price_after = consolidation.average_price_after
+                action.total_cost_basis = consolidation.total_cost_basis
                 cur.execute("SELECT corporate_action_id, portfolio_id, asset_id, action_type, effective_date, actor_user_id, evidence_ref, idempotency_key, payload_hash, quantity_before, quantity_after, average_price_before, average_price_after, total_cost_basis, cash_balance, profit_buffer, ledger_entry_id, recorded_at FROM portfolio_corporate_actions WHERE portfolio_id=%s AND idempotency_key=%s", (portfolio_id, idempotency_key))
                 prior = cur.fetchone()
                 if prior: