Support YAML list format for whitelist_hosts config

internal/config/config.go

@@ -147,21 +147,40 @@ func getStringSlice(sc *smartconfig.Config, key string) []string {
 		return nil
 	}
 
-	val, err := sc.GetString(key)
-	if err != nil || val == "" {
+	val, ok := sc.Get(key)
+	if !ok || val == nil {
 		return nil
 	}
 
-	// Parse comma-separated values
-	parts := strings.Split(val, ",")
-	result := make([]string, 0, len(parts))
-
-	for _, part := range parts {
-		trimmed := strings.TrimSpace(part)
-		if trimmed != "" {
-			result = append(result, trimmed)
+	// Handle YAML list format
+	if slice, ok := val.([]interface{}); ok {
+		result := make([]string, 0, len(slice))
+		for _, item := range slice {
+			if str, ok := item.(string); ok {
+				trimmed := strings.TrimSpace(str)
+				if trimmed != "" {
+					result = append(result, trimmed)
+				}
+			}
 		}
+
+		return result
 	}
 
-	return result
+	// Fall back to comma-separated string for backwards compatibility
+	if str, ok := val.(string); ok && str != "" {
+		parts := strings.Split(str, ",")
+		result := make([]string, 0, len(parts))
+
+		for _, part := range parts {
+			trimmed := strings.TrimSpace(part)
+			if trimmed != "" {
+				result = append(result, trimmed)
+			}
+		}
+
+		return result
+	}
+
+	return nil
 }