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/react-remove-scroll-bar/dist/es5/utils.d.ts

@@ -0,0 +1,14 @@
+export declare type GapMode = 'padding' | 'margin';
+export interface GapOffset {
+    left: number;
+    top: number;
+    right: number;
+    gap: number;
+}
+export declare const zeroGap: {
+    left: number;
+    top: number;
+    right: number;
+    gap: number;
+};
+export declare const getGapWidth: (gapMode?: GapMode) => GapOffset;