Fix code formatting and linting issues

- Updated GitHub Actions workflow to use correct flake8 configuration
- Fixed line length issues by using 88 characters as configured
- Removed unused imports and trailing whitespace
- Fixed f-string placeholders and unused variables
- All linting checks now pass with project configuration

🤖 Generated with [Claude Code](https://claude.ai/code)

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

wikijs/endpoints/__init__.py

@@ -19,4 +19,4 @@ from .pages import PagesEndpoint
 __all__ = [
     "BaseEndpoint",
     "PagesEndpoint",
-]
+]