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/models/__init__.py

@@ -6,6 +6,6 @@ from .page import Page, PageCreate, PageUpdate
 __all__ = [
     "BaseModel",
     "Page",
-    "PageCreate", 
+    "PageCreate",
     "PageUpdate",
-]
+]