Replays that match the candidate's screen

What changed

• Session replays now show the candidate's own editor, file tree, and header. New recordings also keep the panel sizes the candidate chose.
• The candidate report now says, right next to the score, when a build was not running at the moment it was submitted. The candidate's agent now stops retrying when its edits no longer change any files.
• Asking the recruiting assistant to change one detail of a proposed assessment now changes only that detail, and the card says if a question was dropped. Algorithmic questions from the library open in Python for candidates and use the same labeled sections as the practice library.