Features:

- Node group CRUD operations with traffic-based filtering
  - Three grouping modes: average distribution, subscription-based, and traffic-based
  - Automatic and manual group recalculation with history tracking
  - Group assignment preview before applying changes
  - User subscription group locking to prevent automatic reassignment
  - Subscribe-to-group mapping configuration
  - Group calculation history and detailed reports
  - System configuration for group management (enabled/mode/auto_create)

  Database:
  - Add node_group table for group definitions
  - Add group_history and group_history_detail tables for tracking
  - Add node_group_ids (JSON) to nodes and subscribe tables
  - Add node_group_id and group_locked fields to user_subscribe table
  - Add migration files for schema changes

ppanel.api

@@ -30,6 +30,7 @@ import (
 	"apis/admin/ads.api"
 	"apis/admin/marketing.api"
 	"apis/admin/application.api"
+	"apis/admin/group.api"
 	"apis/public/user.api"
 	"apis/public/subscribe.api"
 	"apis/public/redemption.api"