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/oauth/storage.py

@@ -13,6 +13,7 @@ from .schemas import AccessToken, AuthorizationCode, RefreshToken
 
 logger = logging.getLogger(__name__)
 
+
 class BaseStorage:
     """Base storage interface"""
 
@@ -43,6 +44,7 @@ class BaseStorage:
     def revoke_refresh_token(self, token: str) -> bool:
         raise NotImplementedError
 
+
 class JSONStorage(BaseStorage):
     """
     JSON file storage for OAuth tokens.
@@ -199,6 +201,7 @@ class JSONStorage(BaseStorage):
         logger.info(f"Cleaned up {len(codes) - len(cleaned_codes)} expired authorization codes")
         logger.info(f"Cleaned up {len(tokens) - len(cleaned_tokens)} expired access tokens")
 
+
 def get_storage() -> BaseStorage:
     """
     Get storage instance based on environment.