fix: resolve CI linting and type checking errors

scaffoldforge/config.py

@@ -2,7 +2,7 @@
 
 import os
 from pathlib import Path
-from typing import Any, Dict, Optional
+from typing import Any, Optional
 
 import yaml
 
@@ -11,7 +11,7 @@ class Config:
     """Configuration management class."""
 
     _instance: Optional["Config"] = None
-    _config: Dict[str, Any] = {}
+    _config: dict[str, Any] = {}
 
     def __new__(cls) -> "Config":
         if cls._instance is None:
@@ -78,20 +78,22 @@ class Config:
         """Load configuration from YAML file."""
         path = Path(config_path)
         if path.exists():
-            with open(path, "r") as f:
+            with open(path) as f:
                 user_config = yaml.safe_load(f) or {}
                 self._config.update(user_config)
 
-    def get(self, key: str, default: Any = None) -> Any:
+    def get(self, key: str, default: Any | None = None) -> Any:
         """Get configuration value using dot notation."""
         keys = key.split(".")
-        value = self._config
+        value: Any = self._config
         for k in keys:
             if isinstance(value, dict):
                 value = value.get(k)
             else:
                 return default
-        return value if value is not None else default
+            if value is None:
+                return default
+        return value
 
     def get_github_token(self) -> Optional[str]:
         """Get GitHub token from environment or config."""