fix: enforce restricted fund balance check before recording expenses (GAAP)

source/packages/plg_system_mokosuitenpo/src/Helper/FundAccountingHelper.php

@@ -50,6 +50,19 @@ class FundAccountingHelper
 
 		if (!$fundType) throw new \RuntimeException('Fund not found');
 
+		// Enforce balance check on restricted funds (GAAP compliance)
+		if ($fundType === 'restricted' || $fundType === 'temporarily_restricted') {
+			$db->setQuery($db->getQuery(true)
+				->select('COALESCE((SELECT SUM(d.amount) FROM #__mokosuitenpo_donations d WHERE d.fund_id = ' . (int) $fundId . '), 0)'
+					. ' - COALESCE((SELECT SUM(e.amount) FROM #__mokosuitenpo_fund_expenses e WHERE e.fund_id = ' . (int) $fundId . '), 0) AS balance')
+				->from('DUAL'));
+			$balance = (float) $db->loadResult();
+
+			if ($amount > $balance) {
+				throw new \RuntimeException('Insufficient balance in restricted fund (available: $' . number_format($balance, 2) . ', requested: $' . number_format($amount, 2) . ')');
+			}
+		}
+
 		$expense = (object) [
 			'fund_id'     => $fundId,
 			'amount'      => $amount,