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/auth/api_key.py

@@ -4,20 +4,20 @@ This module implements API key authentication for Wiki.js instances.
 API keys are typically used for server-to-server authentication.
 """
 
-from typing import Dict, Optional
+from typing import Dict
 
 from .base import AuthHandler
 
 
 class APIKeyAuth(AuthHandler):
     """API key authentication handler for Wiki.js.
-    
+
     This handler implements authentication using an API key, which is
     included in the Authorization header as a Bearer token.
-    
+
     Args:
         api_key: The API key string from Wiki.js admin panel.
-        
+
     Example:
         >>> auth = APIKeyAuth("your-api-key-here")
         >>> client = WikiJSClient("https://wiki.example.com", auth=auth)
@@ -25,35 +25,35 @@ class APIKeyAuth(AuthHandler):
 
     def __init__(self, api_key: str) -> None:
         """Initialize API key authentication.
-        
+
         Args:
             api_key: The API key from Wiki.js admin panel.
-            
+
         Raises:
             ValueError: If api_key is empty or None.
         """
         if not api_key or not api_key.strip():
             raise ValueError("API key cannot be empty")
-        
+
         self._api_key = api_key.strip()
 
     def get_headers(self) -> Dict[str, str]:
         """Get authentication headers with API key.
-        
+
         Returns:
             Dict[str, str]: Headers containing the Authorization header.
         """
         return {
             "Authorization": f"Bearer {self._api_key}",
-            "Content-Type": "application/json"
+            "Content-Type": "application/json",
         }
 
     def is_valid(self) -> bool:
         """Check if API key is valid.
-        
+
         For API keys, we assume they're valid if they're not empty.
         Actual validation happens on the server side.
-        
+
         Returns:
             bool: True if API key exists, False otherwise.
         """
@@ -61,29 +61,30 @@ class APIKeyAuth(AuthHandler):
 
     def refresh(self) -> None:
         """Refresh authentication credentials.
-        
+
         API keys don't typically need refreshing, so this is a no-op.
         If the API key becomes invalid, a new one must be provided.
         """
         # API keys don't refresh - they're static until manually replaced
-        pass
 
     @property
     def api_key(self) -> str:
         """Get the masked API key for logging/debugging.
-        
+
         Returns:
             str: Masked API key showing only first 4 and last 4 characters.
         """
         if len(self._api_key) <= 8:
             return "*" * len(self._api_key)
-        
-        return f"{self._api_key[:4]}{'*' * (len(self._api_key) - 8)}{self._api_key[-4:]}"
+
+        return (
+            f"{self._api_key[:4]}{'*' * (len(self._api_key) - 8)}{self._api_key[-4:]}"
+        )
 
     def __repr__(self) -> str:
         """String representation of the auth handler.
-        
+
         Returns:
             str: Safe representation with masked API key.
         """
-        return f"APIKeyAuth(api_key='{self.api_key}')"
+        return f"APIKeyAuth(api_key='{self.api_key}')"