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/d3-format/README.md

@@ -0,0 +1,12 @@
+# d3-format
+
+<a href="https://d3js.org"><img src="https://github.com/d3/d3/raw/main/docs/public/logo.svg" width="256" height="256"></a>
+
+This module formats numbers for human consumption, with a consistent output allowing comparison. Grouped digits, currencies, scientific notation…
+
+## Resources
+
+- [Documentation](https://d3js.org/d3-format)
+- [Examples](https://observablehq.com/@d3/d3-format)
+- [Releases](https://github.com/d3/d3-format/releases)
+- [Getting help](https://d3js.org/community)