Add JSON files for Payment Gateway Interface and API documentation updates

- Created a new JSON file for the PaymentGatewayInterface.php, detailing its methods and return types.
- Added a JSON file for payment.md, documenting various API endpoints and their parameters, responses, and errors.
- Introduced a JSON file for fix-admin-modal-and-calendar.md, outlining issues and solutions related to admin modal and calendar functionalities.

assets/admin/pages/FinancialReportPage.tsx

@@ -93,7 +93,7 @@ export default function FinancialReportPage() {
         </div>
       </div>
 
-      <div className="stat-grid" style={{ gridTemplateColumns: 'repeat(5,1fr)', marginBottom: 'var(--gap)' }}>
+      <div className="stat-grid" style={{ marginBottom: 'var(--gap)' }}>
         {cards.map((c) => (
           <div key={c.label} className="stat" style={{ background: c.bg }}>
             <div className="stat-label">{c.label}</div>