Address PR Feedback

Handle an existing GitHub PR from review intake through local fixes, validation, push, and reviewer-facing replies. Treat PR feedback as broader than inline threads: review bodies, issue comments, bot summaries, "outside diff" sections, and follow-up comments can all contain actionable items.

If the task covers multiple dependent or stacked PRs, read workflows/stacked-prs.md before mapping, retargeting, or changing any PR branch in the stack. Select its feedback-only or authorized landing route, then apply the intake, fix, reply, and per-PR completion checks below to each current PR. Defer the user-facing completion response until the entire selected stack satisfies the workflow's completion gate.

Intake