设备管理模块方法转换为DTO模式，修复long类型接收雪花ID丢失精度的问题

Model/Dto/Asset/EquipmentDto.cs

@@ -7,8 +7,8 @@ namespace Model.Dto.Asset
     /// </summary>
     public class EquipmentDto
     {
-        /// <summary>主键 Id（long → string）</summary>
-        public string Id { get; set; }
+        /// <summary>主键 Id（long → string；入参可空，新增时无需传递）</summary>
+        public string? Id { get; set; }
 
         /// <summary>删除状态（0、未删除；1、已删除）</summary>
         public byte IsDel { get; set; }
@@ -22,8 +22,8 @@ namespace Model.Dto.Asset
         /// <summary>设备名称</summary>
         public string? Name { get; set; }
 
-        /// <summary>设备分类Id（关联 EquipmentCategoryEntity.Id）</summary>
-        public long CategoryId { get; set; }
+        /// <summary>设备分类Id（关联 EquipmentCategoryEntity.Id，雪花 Id 转 string 防精度丢失；可空，未分类时为 "0" 或不传）</summary>
+        public string? CategoryId { get; set; }
 
         /// <summary>设备类型</summary>
         public string? Type { get; set; }