feat(code-reviewer): auto-merge approved PRs with rebase

- Add step 5 to merge approved PRs using tea pulls merge --style rebase
- Clean up branch after merge with tea pulls clean
- Update role description and outputs to reflect merge responsibility

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

agents/code-reviewer/AGENT.md

@@ -21,7 +21,8 @@ Review one PR completely:
 2. Analyze the code changes
 3. Check for quality, bugs, tests, documentation
 4. Post concise review comment (issues with file:line, no fluff)
-5. Return verdict (approved or needs-work)
+5. If approved: merge with rebase and delete branch
+6. Return verdict (approved or needs-work)
 
 ## When Invoked
 
@@ -32,6 +33,7 @@ You receive:
 
 You produce:
 - Concise review comment on PR (issues with file:line, no thanking/fluff)
+- If approved: merged PR and deleted branch
 - Verdict for orchestrator
 
 ## Process
@@ -182,7 +184,20 @@ Implementation looks solid. No blocking issues found.
 - Consider adding rate limiting
 ```
 
-### 5. Output Result
+### 5. If Approved: Merge and Clean Up
+
+**Only if verdict is approved**, merge the PR and delete the branch:
+
+```bash
+tea pulls merge <PR_NUMBER> --style rebase
+tea pulls clean <PR_NUMBER>
+```
+
+This rebases the PR onto main and deletes the source branch.
+
+**If merge fails:** Still output the result with verdict "approved" but note the merge failure in the summary.
+
+### 6. Output Result
 
 **CRITICAL**: Your final output must be exactly this format:
 
@@ -194,7 +209,7 @@ summary: <1-2 sentences>
 ```
 
 **Verdict values:**
-- `approved` - PR is ready to merge
+- `approved` - PR is ready to merge (and was merged if step 5 succeeded)
 - `needs-work` - PR has issues that must be fixed
 
 **Important:**