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/lodash/_Promise.js

@@ -0,0 +1,7 @@
+var getNative = require('./_getNative'),
+    root = require('./_root');
+
+/* Built-in method references that are verified to be native. */
+var Promise = getNative(root, 'Promise');
+
+module.exports = Promise;