update API for more simple approach.

SoilMoistureAPI/Models/SoilMoistureFlat.cs

@@ -0,0 +1,12 @@
+namespace SoilMoistureAPI.Models
+{
+    public class SoilMoistureFlat
+    {
+        public int Id { get; set; }
+        public string DeviceId { get; set; }         // Unique identifier for the sensor device
+        public float MoistureLevel { get; set; }       // Current moisture reading
+        public DateTime Timestamp { get; set; } = DateTime.UtcNow;
+        public string Nickname { get; set; }     // A friendly name for the device
+    }
+
+}