Added attempt history to the dashboard

A student emailed me with a feature request: to make attempt summaries permanently available for students to view. It was a good suggestion and relatively easy to implement, so it is now live. Thank you, Abdul, for the suggestion!

I have also fixed a few errors pointed out by several students. Thank you to everyone who notified me. These corrections are now live, and both the exam simulator and PDF downloads have been updated.

A reminder that the first five papers are considered fully polished. The remaining five are on my list for a full review.