lookup province, district, subDistrict IDs with parent filtering

Models/SubDistrict.cs

@@ -12,6 +12,9 @@ namespace BMA.EHR.Recurit.Exam.Service.Models
         [MaxLength(10), Column(Order = 2), Comment("รหัสไปรษณีย์")]
         public string? zipCode { get; set; } = null;
 
+        [Column(Order = 3), Comment("รหัสอ้างอิงอำเภอ")]
+        public Guid? districtId { get; set; } = null;
+
         // [Column(Order = 3), Comment("สถานะการใช้งาน")]
         // public bool IsActive { get; set; } = true;