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/escalade/sync/index.d.mts

@@ -0,0 +1,9 @@
+export type Callback = (
+	directory: string,
+	files: string[],
+) => string | false | void;
+
+export default function (
+	directory: string,
+	callback: Callback,
+): string | void;