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/collectElements.js

@@ -0,0 +1,12 @@
+export default function collectElements(node, direction) {
+  var nextNode = null;
+  var nodes = [];
+  nextNode = node ? node[direction] : null;
+
+  while (nextNode && nextNode.nodeType !== 9) {
+    nodes.push(nextNode);
+    nextNode = nextNode[direction] || null;
+  }
+
+  return nodes;
+}