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/tr46/lib/statusMapping.js

@@ -0,0 +1,11 @@
+"use strict";
+
+module.exports.STATUS_MAPPING = {
+  mapped: 1,
+  valid: 2,
+  disallowed: 3,
+  disallowed_STD3_valid: 4,
+  disallowed_STD3_mapped: 5,
+  deviation: 6,
+  ignored: 7
+};