Add new Backend structure with proper .NET 8 projects

src/Backend/DiunaBI.Database/Migrations/20250529093632_LayersIsCancelled.cs

@@ -0,0 +1,29 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace DiunaBI.Core.Migrations
+{
+    /// <inheritdoc />
+    public partial class LayersIsCancelled : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<bool>(
+                name: "IsCancelled",
+                table: "Layers",
+                type: "bit",
+                nullable: false,
+                defaultValue: false);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "IsCancelled",
+                table: "Layers");
+        }
+    }
+}