docs: add explicit no-PR rule for maintainer repos

Polecats were creating GitHub PRs instead of using gt done to submit
to the Refinery. Added clear conditional language:

- If repo is steveyegge/beads or steveyegge/gastown: NEVER create PRs
- Polecats use gt done → Refinery merges
- Crew workers push directly to main
- PRs are for external contributors only

This fixes a prompting gap that led to PR #292 being created incorrectly.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

templates/polecat-CLAUDE.md

@@ -162,6 +162,16 @@ The `gt done --exit` command:
 - Exits your session immediately (no idle waiting)
 - Witness handles cleanup, Refinery merges your branch
 
+### No PRs in Maintainer Repos
+
+If the remote origin is `steveyegge/beads` or `steveyegge/gastown`:
+- **NEVER create GitHub PRs** - you have direct push access
+- Polecats: use `gt done` → Refinery merges to main
+- Crew workers: push directly to main
+
+PRs are for external contributors submitting to repos they don't own.
+Check `git remote -v` if unsure about repo ownership.
+
 ### The Landing Rule
 
 > **Work is NOT landed until it's on `main` OR in the Refinery MQ.**