address-pr-feedback

Address review feedback and merge conflicts on an existing PR end to end in any project. Use for "address PR feedback", "fix review comments", or "resolve PR conflicts". For authorized feedback fixes, assess the concern, ship validated code to the same PR branch, reply with commit/test evidence, then resolve only fully addressed review threads. Preserve unrelated work and PR state; never merge the PR. Plan-only and conflict-only requests remain scoped to that intent.