Fix PR Review Feedback

Turn a pile of review comments into a set of committed fixes plus a set of honest replies. The deliverable is both — a PR where every thread got an answer, not one where every thread got a code change.

Let SKILL=/path/to/this/skill — the directory holding this SKILL.md. Commands run from the repository being worked on, not from the skill directory. Needs Python 3.11+, git, and an authenticated gh with network access; fetch_pr_feedback.py queries the GraphQL API through gh and can do nothing without it. If gh auth status fails, say so — never reconstruct review threads from memory or from the diff.

Collect everything first