Agents window replay and profile share cards

What changed

• Full session replay now marks when the candidate was working in the Agents window, so that time no longer looks idle.
• In the Agents window, the problem statement is now a card you can drag aside while the chat stays in view. Recruiting Copilot can also find built-in build questions, such as an analog clock or Connect Four, and reuse them.
• Shared profile links now show a branded preview card with your level and progress. A new dashboard card opens a guided practice run of the AI coding workspace, where nothing is saved or scored.