feat: redesign Exams List page to show submitted custom exams

- Added Custom Exams tab showing all exams from Generation page
- Displays title, module badges, duration, and status
- Added Create Exam button
- Kept Exam Sessions tab for institutional sessions
- Search filters across exams

Made-with: Cursor

node_modules/vitest/dist/snapshot.js

@@ -0,0 +1,4 @@
+export { VitestNodeSnapshotEnvironment as VitestSnapshotEnvironment } from './chunks/node.fjCdwEIl.js';
+import '@vitest/snapshot/environment';
+import './chunks/utils.XdZDrNZV.js';
+import '@vitest/utils';