fix: restore form declaration, fix openDrawer state

apps/admin/src/pages/Students/index.tsx

@@ -86,9 +86,10 @@ const StudentsPage: React.FC = () => {
   const [enrollmentData, setEnrollmentData] = useState<Record<number, EnrollmentInfo[]>>({});
   const [drawerOpen, setDrawerOpen] = useState(false);
   const [drawerData, setDrawerData] = useState<any>(null);
+  const [drawerLoading, setDrawerLoading] = useState(false);
+  const [form] = Form.useForm();
 
   const openDrawer = async (studentId: number) => {
-    setDrawerStudentId(studentId);
     setDrawerOpen(true);
     setDrawerLoading(true);
     try {