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/date-fns/_lib/defaultLocale.js

@@ -0,0 +1,8 @@
+"use strict";
+Object.defineProperty(exports, "defaultLocale", {
+  enumerable: true,
+  get: function () {
+    return _index.enUS;
+  },
+});
+var _index = require("../locale/en-US.js");