Add pre-commit hooks for linting and formatting

Set up pre-commit framework with ruff (backend) and ESLint/Prettier/tsc
(frontend) hooks to catch issues locally before CI. Auto-format all
frontend files with Prettier to comply with the new check.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/admin/FormModal.tsx

@@ -55,7 +55,11 @@ export function FormModal({
                 onBlur={() => setConfirmingDelete(false)}
                 className="px-4 py-2 text-sm font-medium rounded-md text-red-600 dark:text-red-400 border border-red-300 dark:border-red-600 hover:bg-red-50 dark:hover:bg-red-900/20 disabled:opacity-50"
               >
-                {isDeleting ? 'Deleting...' : confirmingDelete ? 'Confirm?' : 'Delete'}
+                {isDeleting
+                  ? 'Deleting...'
+                  : confirmingDelete
+                    ? 'Confirm?'
+                    : 'Delete'}
               </button>
             )}
             <div className="flex-1" />