docs(prd-6): mark M6 complete — tag mode with code changes validated

- Branch creation, commit push, bot attribution all verified (run #198)
- 1 bug found: prompt template used quick_pull=1 instead of expand=1
- Fix committed in f08b1b4, validates after merge to main

Progress: 87% complete — M7 (docs update) remaining

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

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

@@ -91,13 +91,19 @@ Systematically exercise each untested scenario on the live Forgejo instance (git
   - **Also discovered**: Forgejo's API `PATCH /issues/{index}` with `{"assignees": ["user"]}` (plural array) returns 404. Must use deprecated singular `{"assignee": "user"}` field instead.
   - **Key learning**: On Forgejo, the `issues/assigned` webhook payload structure differs from GitHub — the assigned user is nested under `issue.assignee`, not at the top-level `assignee` field. Same pattern as M2's missing top-level `comment` object.
 
-- [ ] **M6: Test tag mode with code changes (branch creation)**
+- [x] **M6: Test tag mode with code changes (branch creation)**
 
-  - Create an issue requesting a code change (e.g., "add a comment to file X")
-  - Trigger Claude via `@claude` mention
-  - Verify: Claude creates a branch, pushes commits, links the branch in tracking comment
-  - Verify the Forgejo-specific PR compare URL format is correct
-  - **Validation**: Claude successfully creates a branch with code changes on Forgejo
+  - Created test issue #21 requesting creation of `test/e2e-prd6-m6.txt` ✓
+  - Triggered Claude via `@claude` mention in issue comment ✓
+  - Verify: Claude creates a branch, pushes commits, links the branch in tracking comment ✓
+    - Branch: `claude/issue-21-20260226-0917`
+    - Commit: `59f7e4e` by `claude <claude@wxs.ro>` (bot identity correct)
+    - File content verified via API: matches requested content
+  - Verify the Forgejo-specific PR compare URL format is correct ✓ (after fix, see below)
+  - **Validation**: Claude successfully creates a branch with code changes on Forgejo ✓ (run #198, 41s)
+  - **Bug found & fixed**:
+    1. `f08b1b4`: Prompt template in `src/create-prompt/index.ts` (lines 604, 794) hardcoded `quick_pull=1` (GitHub-specific) in the "Create a PR" URL. On Forgejo, this param is ignored so the compare page doesn't auto-expand the PR creation form. Forgejo uses `expand=1`. Fix: made prompt template platform-aware via `detectPlatform()`. Note: `updateForgejoCommentBody()` extracts PR URLs from comment content (`prLinkFromContent`) with priority over the URL from `update-comment-link.ts`, so the prompt template is the correct fix location.
+  - **Key learning**: The PR compare URL appears in two places — the prompt template (used by Claude to write the URL into comment body) and `update-comment-link.ts` (post-execution update). Because `updateForgejoCommentBody()` prioritizes URLs found in existing content, both must use the correct platform-specific query parameter. Fix validated after merge to `main` (workflow runs from default branch for `issue_comment` events).
 
 - [ ] **M7: Update documentation with E2E results**
   - Update `docs/forgejo.md` E2E status table with results for all 5 scenarios
@@ -126,6 +132,7 @@ Systematically exercise each untested scenario on the live Forgejo instance (git
 | Creating issue with label fires duplicate runs           | RESOLVED: label check only on labeled event, not on opened   |
 | Forgejo assigned payload lacks top-level assignee        | RESOLVED: fallback to issue.assignee.login in trigger.ts     |
 | Forgejo API assignees array field returns 404            | RESOLVED: use deprecated singular assignee field instead     |
+| Prompt template hardcodes quick_pull=1 in PR compare URL | RESOLVED: platform-aware expand=1 for Forgejo in prompt      |
 
 ## Success Criteria