Refactor payment request handling to support role change top-ups

- Updated the `PaymentRequest` model to include a new `Kind` property, distinguishing between `Subscription` and `RoleChangeTopUp` requests.
- Modified the `TelegramNotifier` to accommodate the new request type, ensuring accurate notifications for role change top-ups.
- Enhanced the `ConfirmPaymentRequestCommandHandler` to handle role change top-ups without extending the billing period, reflecting the new payment logic.
- Updated various application components and tests to support the new payment request structure and ensure proper functionality.
- Revised API documentation to clarify the behavior of role change top-ups and their impact on billing.

backend/src/PnvPanel.Infrastructure/Persistence/Configurations/PaymentRequestConfiguration.cs

@@ -11,6 +11,7 @@ public class PaymentRequestConfiguration : IEntityTypeConfiguration<PaymentReque
         builder.ToTable("PaymentRequests");
         builder.HasKey(x => x.Id);
 
+        builder.Property(x => x.Kind).HasConversion<string>().HasMaxLength(32);
         builder.Property(x => x.Period).HasConversion<string>().HasMaxLength(32);
         builder.Property(x => x.Status).HasConversion<string>().HasMaxLength(32);
         builder.Property(x => x.RejectionReason).HasMaxLength(500);

backend/src/PnvPanel.Infrastructure/Persistence/Migrations/20260719130201_AddPaymentRequestKind.cs

@@ -0,0 +1,52 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace PnvPanel.Infrastructure.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddPaymentRequestKind : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<string>(
+                name: "Period",
+                table: "PaymentRequests",
+                type: "character varying(32)",
+                maxLength: 32,
+                nullable: true,
+                oldClrType: typeof(string),
+                oldType: "character varying(32)",
+                oldMaxLength: 32);
+
+            migrationBuilder.AddColumn<string>(
+                name: "Kind",
+                table: "PaymentRequests",
+                type: "character varying(32)",
+                maxLength: 32,
+                nullable: false,
+                defaultValue: "Subscription");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "Kind",
+                table: "PaymentRequests");
+
+            migrationBuilder.AlterColumn<string>(
+                name: "Period",
+                table: "PaymentRequests",
+                type: "character varying(32)",
+                maxLength: 32,
+                nullable: false,
+                defaultValue: "",
+                oldClrType: typeof(string),
+                oldType: "character varying(32)",
+                oldMaxLength: 32,
+                oldNullable: true);
+        }
+    }
+}

backend/src/PnvPanel.Infrastructure/Persistence/Migrations/AppDbContextModelSnapshot.cs

@@ -293,11 +293,15 @@ namespace PnvPanel.Infrastructure.Persistence.Migrations
                     b.Property<Guid?>("DecidedBy")
                         .HasColumnType("uuid");
 
-                    b.Property<string>("Period")
+                    b.Property<string>("Kind")
                         .IsRequired()
                         .HasMaxLength(32)
                         .HasColumnType("character varying(32)");
 
+                    b.Property<string>("Period")
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
                     b.Property<string>("RejectionReason")
                         .HasMaxLength(500)
                         .HasColumnType("character varying(500)");