feat(toolchain): add PR synchronize and review comment notifications

- pull_request.synchronize: notify reviewer to re-review after push
- pull_request_review COMMENTED: notify PR author of review comments
- New templates: review_updated.md, review_comment.md
- Idempotency: add review ID to content dedup key
- Design doc: docs/design/23-toolchain-pr-lifecycle.md

src/daemon/toolchain_templates.py

@@ -21,6 +21,8 @@ _TEMPLATE_MAP: Dict[str, str] = {
     "issue_assigned": "issue_assigned.md",
     "ci_failure": "ci_failure.md",
     "deploy_failure": "deploy_failure.md",
+    "review_updated": "review_updated.md",
+    "review_comment": "review_comment.md",
 }
 
 # 模板缓存