AskUserQuestion improvements

We've cleaned up the UI for the AskUserQuestion tool to make it fully keyboard navigable.

Improvements

• You can now see GitHub comment edits in Conductor
• Drag and drop folders onto the Composer to mention them
• Add button to copy PR link
• You can now add a git prefix that doesn't end in / in Settings → Git
• Updated Codex reasoning level default from minimal to low

Fixes

• We've made rebase detection more reliable in various parts of the app, including spotlight testing and archiving
• Review session now respects Codex thinking level
• ⌃V to mark a file as viewed now works when the chat is focused
• Updated Codex reasoning level default from minimal to low

Misc

• Various UI cleanup