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>

core/auth.py

@@ -10,6 +10,7 @@ import secrets
 
 logger = logging.getLogger(__name__)
 
+
 class AuthManager:
     """
     Manage authentication for MCP server.
@@ -115,9 +116,11 @@ class AuthManager:
         """Check if a project has its own API key."""
         return project_id in self.project_keys
 
+
 # Global authentication manager instance
 _auth_manager: AuthManager | None = None
 
+
 def get_auth_manager() -> AuthManager:
     """Get the global authentication manager instance."""
     global _auth_manager