fix(prd-7): M6 documentation accuracy review — 10 corrections across docs/forgejo.md and CLAUDE.md

- Fix actor validation: "skipped entirely" → "bot-type check skipped; self-trigger guard active"
- Fix permission check: document getCollaboratorPermissionLevel() primary with repos.get() fallback
- Add platform detection cross-validation security note (rejects Forgejo override on github.com)
- Fix update-with-branch.ts description: "PR compare URL" → "branch link" (URL is in update-comment-link.ts)
- Add missing update-comment-link.ts to key integration points in CLAUDE.md
- Fix test-action.yml description to match actual validation checks
- Nuance troubleshooting guidance for # in workflow if: expressions
- Verify all Known Limitations still accurate

Progress: 100% complete — all 6 milestones done

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

prds/7-senior-review-forgejo.md

@@ -101,7 +101,7 @@ Perform a thorough, documented code review of all Forgejo-related changes. The r
   - Code comments: are complex decisions documented?
   - **Deliverable**: Code quality fixes applied
 
-- [ ] **M6: Documentation accuracy review**
+- [x] **M6: Documentation accuracy review**
   - Cross-check `docs/forgejo.md` against actual code behavior
   - Verify all "Known Limitations" are still accurate
   - Check that code examples and configuration snippets work