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

internal/model/node/node.go

@@ -1,25 +1,73 @@
 package node
 
 import (
+	"database/sql/driver"
+	"encoding/json"
 	"time"
 
 	"github.com/perfect-panel/server/pkg/logger"
 	"gorm.io/gorm"
 )
 
+// JSONInt64Slice is a custom type for handling []int64 as JSON in database
+type JSONInt64Slice []int64
+
+// Scan implements sql.Scanner interface
+func (j *JSONInt64Slice) Scan(value interface{}) error {
+	if value == nil {
+		*j = []int64{}
+		return nil
+	}
+
+	// Handle []byte
+	bytes, ok := value.([]byte)
+	if !ok {
+		// Try to handle string
+		str, ok := value.(string)
+		if !ok {
+			*j = []int64{}
+			return nil
+		}
+		bytes = []byte(str)
+	}
+
+	if len(bytes) == 0 {
+		*j = []int64{}
+		return nil
+	}
+
+	// Check if it's a JSON array
+	if bytes[0] != '[' {
+		// Not a JSON array, return empty slice
+		*j = []int64{}
+		return nil
+	}
+
+	return json.Unmarshal(bytes, j)
+}
+
+// Value implements driver.Valuer interface
+func (j JSONInt64Slice) Value() (driver.Value, error) {
+	if len(j) == 0 {
+		return "[]", nil
+	}
+	return json.Marshal(j)
+}
+
 type Node struct {
-	Id        int64     `gorm:"primary_key"`
-	Name      string    `gorm:"type:varchar(100);not null;default:'';comment:Node Name"`
-	Tags      string    `gorm:"type:varchar(255);not null;default:'';comment:Tags"`
-	Port      uint16    `gorm:"not null;default:0;comment:Connect Port"`
-	Address   string    `gorm:"type:varchar(255);not null;default:'';comment:Connect Address"`
-	ServerId  int64     `gorm:"not null;default:0;comment:Server ID"`
-	Server    *Server   `gorm:"foreignKey:ServerId;references:Id"`
-	Protocol  string    `gorm:"type:varchar(100);not null;default:'';comment:Protocol"`
-	Enabled   *bool     `gorm:"type:boolean;not null;default:true;comment:Enabled"`
-	Sort      int       `gorm:"uniqueIndex;not null;default:0;comment:Sort"`
-	CreatedAt time.Time `gorm:"<-:create;comment:Creation Time"`
-	UpdatedAt time.Time `gorm:"comment:Update Time"`
+	Id           int64          `gorm:"primary_key"`
+	Name         string         `gorm:"type:varchar(100);not null;default:'';comment:Node Name"`
+	Tags         string         `gorm:"type:varchar(255);not null;default:'';comment:Tags"`
+	Port         uint16         `gorm:"not null;default:0;comment:Connect Port"`
+	Address      string         `gorm:"type:varchar(255);not null;default:'';comment:Connect Address"`
+	ServerId     int64          `gorm:"not null;default:0;comment:Server ID"`
+	Server       *Server        `gorm:"foreignKey:ServerId;references:Id"`
+	Protocol     string         `gorm:"type:varchar(100);not null;default:'';comment:Protocol"`
+	Enabled      *bool          `gorm:"type:boolean;not null;default:true;comment:Enabled"`
+	Sort         int            `gorm:"uniqueIndex;not null;default:0;comment:Sort"`
+	NodeGroupIds JSONInt64Slice `gorm:"type:json;comment:Node Group IDs (JSON array, multiple groups)"`
+	CreatedAt    time.Time      `gorm:"<-:create;comment:Creation Time"`
+	UpdatedAt    time.Time      `gorm:"comment:Update Time"`
 }
 
 func (n *Node) TableName() string {