docs(prd-6): mark M3 complete — PR review trigger validated

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

prds/6-e2e-test-forgejo-triggers.md

@@ -54,13 +54,16 @@ Systematically exercise each untested scenario on the live Forgejo instance (git
     3. `c3c3eb5`: **Critical** — MCP comment server set `isPullRequestReviewComment=true` on Forgejo, causing every Claude update to try `pulls.updateReviewComment` (404) and silently fail. Fix: detect Forgejo via `GITHUB_API_URL` and route to issue comment API. Also hardened `update-claude-comment.ts` fallback to catch 422 alongside 404, and skipped the wasted `pulls.getReviewComment` call in `update-comment-link.ts` on Forgejo.
   - **Key learning**: On Forgejo, the tracking comment for review comment events is always an issue comment (not a PR review comment reply) because the payload lacks `comment.id`. All update paths must account for this.
 
-- [ ] **M3: Test PR review trigger**
+- [x] **M3: Test PR review trigger**
 
-  - Create a test PR on the repo
-  - Submit a review with `@claude` mention in the review body
-  - Verify: platform detection, context fetching, tracking comment, Claude response
-  - Document any issues and fix them
-  - **Validation**: Claude responds correctly to `@claude` in a PR review
+  - Reused test PR #15 from M2 ✓
+  - Submitted reviews with `@claude` mention in the review body ✓ (review IDs 20, 21, 22)
+  - Verify: platform detection, context fetching, tracking comment, Claude response ✓
+  - Document any issues and fix them ✓ (1 finding, 1 fix, see below)
+  - **Validation**: Claude responds correctly to `@claude` in a PR review ✓ (runs 12080, 12087)
+  - **Finding**: Forgejo sends `pull_request_comment` instead of `pull_request_review` for review submissions — same pattern as M2. The `pull_request_review` trigger and workflow condition (line 21) are dead code on Forgejo.
+  - **Fix** (`e514bf5`→`b21dbd6`): Replaced blind Forgejo auto-trigger in `trigger.ts` with payload-aware `@claude` check that inspects `comment.body` and `review.body` with fallback. Attempted workflow `if:` gating but reverted — Forgejo's `pull_request_comment` payload does not populate `github.event.comment.body` or `github.event.review.body` (run 12084 was skipped).
+  - **Key learning**: On Forgejo, the workflow `if:` condition cannot reliably gate on payload body fields for `pull_request_comment` events. The `@claude` check must happen in application code (`trigger.ts`), not in the workflow condition.
 
 - [ ] **M4: Test label trigger**
 
@@ -100,12 +103,13 @@ Systematically exercise each untested scenario on the live Forgejo instance (git
 ## Risks
 
 | Risk                                                     | Mitigation                                                   |
-| -------------------------------------------------------- | ----------------------------------------------------------- |
+| -------------------------------------------------------- | ------------------------------------------------------------ |
 | Forgejo webhook payloads differ from expected            | Log raw payloads, compare with GitHub format, adapt parsing  |
 | Trigger type not supported by Forgejo Actions            | Document as known limitation, skip gracefully                |
 | Action creates unwanted branches/comments during testing | Use a dedicated test repo or clean up after each test        |
 | Bun mock.module breaks mock tracking on Linux            | RESOLVED: use spyOn on module namespace, never mock.module   |
 | MCP comment updates silently fail on Forgejo             | RESOLVED: route to issue comment API when platform=forgejo   |
+| Workflow if: cannot gate on payload body for Forgejo     | RESOLVED: @claude check moved to trigger.ts application code |
 
 ## Success Criteria