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/locale/bn.d.mts

@@ -0,0 +1,10 @@
+import type { Locale } from "./types.js";
+/**
+ * @category Locales
+ * @summary Bengali locale.
+ * @language Bengali
+ * @iso-639-2 ben
+ * @author Touhidur Rahman [@touhidrahman](https://github.com/touhidrahman)
+ * @author Farhad Yasir [@nutboltu](https://github.com/nutboltu)
+ */
+export declare const bn: Locale;