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/@tootallnate/once/dist/index.d.ts

@@ -0,0 +1,7 @@
+/// <reference types="node" />
+import { EventEmitter } from 'events';
+import { EventNames, EventListenerParameters, AbortSignal } from './types';
+export interface OnceOptions {
+    signal?: AbortSignal;
+}
+export default function once<Emitter extends EventEmitter, Event extends EventNames<Emitter>>(emitter: Emitter, name: Event, { signal }?: OnceOptions): Promise<EventListenerParameters<Emitter, Event>>;