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/esm/hasClass.js

@@ -0,0 +1,10 @@
+/**
+ * Checks if a given element has a CSS class.
+ * 
+ * @param element the element
+ * @param className the CSS class name
+ */
+export default function hasClass(element, className) {
+  if (element.classList) return !!className && element.classList.contains(className);
+  return (" " + (element.className.baseVal || element.className) + " ").indexOf(" " + className + " ") !== -1;
+}