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/dom-helpers/cjs/position.d.ts

@@ -0,0 +1,12 @@
+/**
+ * Returns the relative position of a given element.
+ *
+ * @param node the element
+ * @param offsetParent the offset parent
+ */
+export default function position(node: HTMLElement, offsetParent?: HTMLElement): {
+    top: number;
+    left: number;
+    height: number;
+    width: number;
+};