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/yearsToQuarters.d.ts

@@ -0,0 +1,18 @@
+/**
+ * @name yearsToQuarters
+ * @category Conversion Helpers
+ * @summary Convert years to quarters.
+ *
+ * @description
+ * Convert a number of years to a full number of quarters.
+ *
+ * @param years - The number of years to be converted
+ *
+ * @returns The number of years converted in quarters
+ *
+ * @example
+ * // Convert 2 years to quarters
+ * const result = yearsToQuarters(2)
+ * //=> 8
+ */
+export declare function yearsToQuarters(years: number): number;