Preserve composer edits during in-flight refresh

[mchwang]

Problem

Copilot's current-head review of PR #11 returned no findings but raised a summary concern that edits made while Refresh is in flight may be discarded when the refreshed review renders.

The submission path has regressions for preserving drafts edited during an in-flight action, but Refresh needs its own reproducible check before changing behavior.

Acceptance criteria

• Add a browser regression that holds /api/review, edits the current question or change-request draft after Refresh starts, then releases the response.
• Preserve the newer draft, selected mode, and valid snippet attachment when rendering the refreshed state.
• If the refreshed state invalidates an attachment or item, retain the text and explain what must be reselected instead of silently clearing the draft.
• Confirm navigation and persisted review state still come from the refreshed response.