fix(config): honor XDG config dir on windows

Author: steipete

internal/config/paths.go

@@ -12,6 +12,10 @@ import (
 const AppName = "gogcli"
 
 func Dir() (string, error) {
+	if xdg := strings.TrimSpace(os.Getenv("XDG_CONFIG_HOME")); xdg != "" {
+		return filepath.Join(xdg, AppName), nil
+	}
+
 	base, err := os.UserConfigDir()
 	if err != nil {
 		return "", fmt.Errorf("resolve user config dir: %w", err)