Add default value for PaymentType in Walk entity

This commit introduces a default value of `1` for the `PaymentType` property in the `Walk` entity. The `SqlDbContextModelSnapshot.cs` is updated to reflect this change, and the `SqlDbContext.cs` is configured to set the default value to `WalkPaymentType.MangoPay`. A new migration class `Walk_PaymentType_DefaultSet` is created to apply these changes to the database schema, ensuring that new records in the `Walks` table will have a default `PaymentType` of `1`.

gehGassi.Persistence/Migrations/20250915133307_Walk_PaymentType_DefaultSet.cs

@@ -0,0 +1,36 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace gehGassi.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class Walk_PaymentType_DefaultSet : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<int>(
+                name: "PaymentType",
+                table: "Walks",
+                type: "int",
+                nullable: false,
+                defaultValue: 1,
+                oldClrType: typeof(int),
+                oldType: "int");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<int>(
+                name: "PaymentType",
+                table: "Walks",
+                type: "int",
+                nullable: false,
+                oldClrType: typeof(int),
+                oldType: "int",
+                oldDefaultValue: 1);
+        }
+    }
+}

gehGassi.Persistence/Migrations/SqlDbContextModelSnapshot.cs

@@ -7819,7 +7819,9 @@ namespace gehGassi.Persistence.Migrations
                         .HasColumnType("int");
 
                     b.Property<int>("PaymentType")
-                        .HasColumnType("int");
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("int")
+                        .HasDefaultValue(1);
 
                     b.Property<Point>("PickupLocation")
                         .HasColumnType("geography");

gehGassi.Persistence/SqlDbContext.cs

@@ -383,6 +383,7 @@ namespace gehGassi.Persistence
             builder.Entity<Walk>().OwnsOne(p => p.ReturnAddress);
             builder.Entity<Walk>().Property(c => c.Price).HasColumnType("decimal(18,2)");
             builder.Entity<Walk>().Property(c => c.VoucherAmmount).HasColumnType("decimal(18,2)");
+            builder.Entity<Walk>().Property(c => c.PaymentType).HasDefaultValue(WalkPaymentType.MangoPay);
 
             builder.Entity<WalkComplaint>().HasIndex(c => c.Index);
             builder.Entity<WalkComplaint>().HasOne<Walk>().WithMany().HasForeignKey(c => c.WalkId).OnDelete(DeleteBehavior.Cascade);