docs(prd-6): mark M4 complete — label trigger validated

3 bugs found and fixed:
- Workflow if: expression parser rejects # comments
- Forgejo doesn't populate github.event.action in if: context
- Forgejo sends 'label_updated' instead of 'labeled'

Key learning: normalize Forgejo event action names in context.ts.

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

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

@@ -65,13 +65,19 @@ Systematically exercise each untested scenario on the live Forgejo instance (git
   - **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**
+- [x] **M4: Test label trigger**
 
-  - Create a label (e.g., `claude`) that triggers the action when applied to an issue
-  - Apply the label to a test issue
-  - Verify: trigger detection, context fetching (issue body/title), Claude response
-  - Document any issues and fix them
-  - **Validation**: Claude responds when the configured label is applied to an issue
+  - Created `claude` label (id: 125) on the repo ✓
+  - Applied label to test issues (#17, #18, #19) ✓
+  - Verify: trigger detection, context fetching (issue body/title), Claude response ✓
+  - Document any issues and fix them ✓ (3 bugs found and fixed, see below)
+  - **Validation**: Claude responds when the configured label is applied to an issue ✓ (run 52795, 20s, 2 turns, $0.12)
+  - Also verified: creating issue with label in one go fires exactly 1 run (issue #19)
+  - **Bugs found & fixed**:
+    1. `a864b16`: Workflow `if:` expression parser rejects `#` comments — Forgejo runner's expression lexer treats `#` as invalid token. Moved all comments outside the `if:` block, switched from `|` to `>-` scalar.
+    2. `414c705`→`a864b16`: Forgejo does not populate `github.event.action` in workflow `if:` context for `issues` events (run 12061 skipped despite action being `labeled`). Let all `issues` events through the gate; `trigger.ts` validates.
+    3. `baa007a`: Forgejo sends `label_updated` instead of `labeled` as `eventAction` for issue label events. Added `FORGEJO_EVENT_ACTION_MAP` in `context.ts` to normalize at parse time (same pattern as event name normalization).
+  - **Key learning**: Forgejo's `issues` event action names differ from GitHub — `label_updated` not `labeled`. Normalize in `context.ts` at parse time so all downstream code works unchanged. Creating an issue with a label fires both `opened` and `label_updated` as separate events — do NOT check labels on `opened` to avoid duplicate runs.
 
 - [ ] **M5: Test assignee trigger**
 
@@ -110,6 +116,9 @@ Systematically exercise each untested scenario on the live Forgejo instance (git
 | 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 |
+| Workflow if: expression parser rejects # comments        | RESOLVED: moved comments outside if: block, use >- scalar    |
+| Forgejo event action names differ from GitHub            | RESOLVED: FORGEJO_EVENT_ACTION_MAP normalizes at parse time  |
+| Creating issue with label fires duplicate runs           | RESOLVED: label check only on labeled event, not on opened   |
 
 ## Success Criteria