chore: simayi-approved changes - lint fixes, toolchain improvements, healthz

All changes reviewed and APPROVED in PR #12 (Review ID: 40):
- toolchain_routes: webhook repo/org format compat, content dedup (sha256), closed issue filter
- dispatcher: inform mail crash 误标 done 修复
- ticker: cleanup and improvements
- healthz endpoint
- conftest: integration/e2e deselect markers
- docs: design docs, test-guide updates
- various lint/whitespace fixes across 30 files

src/daemon/mail_notify.py

@@ -108,7 +108,7 @@ def notify_mail_failed(db_path: Path, original_mail_id: str,
         )
         bb.create_task(notify_task)
         logger.info("Mail %s: sent failure notification to %s (original_sender=%s, reason=%s, notify_id=%s)",
-                    original_mail_id, target_agent, from_agent, reason, notify_id)
+                     original_mail_id, target_agent, from_agent, reason, notify_id)
 
     except Exception as e:
         logger.warning("notify_mail_failed: failed to send notification for mail %s: %s", original_mail_id, e)