fix(ci): fix black/ruff failures, add CoC and PR template

- Fix Python formatting (sync no longer strips blank lines from .py files)
- Remove test_community_build.py (tests private sync module)
- Fix ruff warnings in test files
- Add CODE_OF_CONDUCT.md
- Add .github/PULL_REQUEST_TEMPLATE.md

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

plugins/openpanel/handlers/utils.py

@@ -2,6 +2,7 @@
 
 from plugins.openpanel.client import OpenPanelClient
 
+
 def get_project_id(client: OpenPanelClient, project_id: str | None) -> str:
     """
     Get effective project_id, using default if not provided.