update-pr-review-watcher.sh refreshes the deployed script from the repo via a
dedicated self-update checkout (~/pr-review-watcher/.src) that never races the
issue watcher's work clone. Reads the live config for auth, never clobbers the
config (real token), and self-updates. Optional ref arg for pre-merge testing.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
