fix(config): save user config to project root config.yaml

- _find_config() now looks for config.yaml at project root first
- _get_user_config_path() returns project root config.yaml
- config/default_config.yaml remains as template (not for saving)

src/gui/main_window.py

@@ -104,7 +104,7 @@ class MainWindow(ctk.CTk):
         """Find the user configuration file.
 
         Checks common locations:
-        1. config/config.yaml (user's config)
+        1. config.yaml (project root, user's config)
         2. config/default_config.yaml (template, not for saving)
         3. User-specified path via env var
 
@@ -112,14 +112,14 @@ class MainWindow(ctk.CTk):
             Path to user config file, or None if not found.
         """
         app_dir = Path(__file__).parent.parent
-        config_dir = app_dir / "config"
 
-        # 1. Check for user config first
+        # 1. Check for user config at project root
-        user_config = config_dir / "config.yaml"
+        user_config = app_dir / "config.yaml"
         if user_config.exists():
             return user_config
 
         # 2. Check for default config (template)
+        config_dir = app_dir / "config"
         default_config = config_dir / "default_config.yaml"
         if default_config.exists():
             return default_config
@@ -134,13 +134,13 @@ class MainWindow(ctk.CTk):
     def _get_user_config_path(self) -> Path:
         """Get the path to the user config file (config.yaml).
 
-        Creates config.yaml if it doesn't exist.
+        Creates config.yaml in project root if it doesn't exist.
 
         Returns:
             Path to user config file.
         """
         app_dir = Path(__file__).parent.parent
-        config_path = app_dir / "config" / "config.yaml"
+        config_path = app_dir / "config.yaml"
         config_path.parent.mkdir(parents=True, exist_ok=True)
         return config_path