- update the watcher design and automation guide to treat --categorize as sequential ATVM sub-runs rather than one parent run with internal phases
- document that categorized runs should send one Mattermost status per completed grouped sub-run instead of one parent-only final post
- add a --categorize option to the watcher start helper so categorized mode is explicit in watcher startup
- update the watcher implementation to track categorized sub-runs separately, write per-subrun state, and post each completed grouped run once
anthony.wen
d60b8b9b18