Implement billing functionality and enhance role management

- Introduced billing capabilities, allowing users to request payments for subscription periods (3/6/12 months) with admin approval via Telegram.
- Updated role management to include a `BillingEnabled` property, preventing billing for admin roles.
- Enhanced the `CreateRoleCommand` and `UpdateRoleCommand` to accept billing parameters, ensuring proper handling during role creation and updates.
- Added new endpoints for billing management and integrated billing checks into VPN config creation to enforce payment requirements.
- Updated related services, models, and tests to support the new billing features, ensuring comprehensive coverage and functionality.
- Enhanced documentation to reflect the new billing processes and role management changes.

backend/src/PnvPanel.Api/Endpoints/AdminBillingEndpoints.cs

@@ -0,0 +1,91 @@
+using PnvPanel.Api.Common;
+using PnvPanel.Application.Admin.Billing;
+using PnvPanel.Application.Common.Messaging;
+using PnvPanel.Application.Common.Models;
+using PnvPanel.Domain.Billing;
+using PnvPanel.Infrastructure.Identity;
+
+namespace PnvPanel.Api.Endpoints;
+
+public static class AdminBillingEndpoints
+{
+    public static IEndpointRouteBuilder MapAdminBillingEndpoints(this IEndpointRouteBuilder app)
+    {
+        var admin = app.MapGroup("/api/admin/billing")
+            .WithTags("Admin.Billing")
+            .RequireAuthorization(policy => policy.RequireRole(RoleNames.Admin));
+
+        admin.MapGet("/settings", GetSettings).Produces<BillingSettingsDto>();
+        admin.MapPut("/settings", UpdateSettings).Produces<BillingSettingsDto>();
+        admin
+            .MapGet("/requests", ListRequests)
+            .Produces<PagedList<AdminPaymentRequestDto>>();
+        admin
+            .MapPost("/requests/{id:guid}/confirm", ConfirmRequest)
+            .Produces(StatusCodes.Status204NoContent);
+        admin
+            .MapPost("/requests/{id:guid}/reject", RejectRequest)
+            .Produces(StatusCodes.Status204NoContent);
+
+        return app;
+    }
+
+    private static async Task<IResult> GetSettings(ISender sender, CancellationToken cancellationToken)
+    {
+        var result = await sender.Send(new GetBillingSettingsQuery(), cancellationToken);
+        return result.ToHttpResult();
+    }
+
+    private static async Task<IResult> UpdateSettings(
+        UpdateBillingSettingsCommand command,
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var result = await sender.Send(command, cancellationToken);
+        return result.ToHttpResult();
+    }
+
+    private static async Task<IResult> ListRequests(
+        [AsParameters] ListPaymentRequestsRequest request,
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var query = new ListPaymentRequestsQuery(request.Status, request.Page, request.PageSize);
+        var result = await sender.Send(query, cancellationToken);
+        return result.ToHttpResult();
+    }
+
+    private static async Task<IResult> ConfirmRequest(
+        Guid id,
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var result = await sender.Send(new ConfirmPaymentRequestCommand(id), cancellationToken);
+        return result.ToHttpResult();
+    }
+
+    private static async Task<IResult> RejectRequest(
+        Guid id,
+        RejectPaymentRequestBody body,
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var result = await sender.Send(
+            new RejectPaymentRequestCommand(id, body.Reason),
+            cancellationToken
+        );
+        return result.ToHttpResult();
+    }
+}
+
+public sealed record ListPaymentRequestsRequest(
+    PaymentRequestStatus? Status,
+    int Page = 1,
+    int PageSize = 20
+);
+
+public sealed record RejectPaymentRequestBody(string? Reason);

backend/src/PnvPanel.Api/Endpoints/BillingEndpoints.cs

@@ -0,0 +1,84 @@
+using PnvPanel.Api.Common;
+using PnvPanel.Application.Billing;
+using PnvPanel.Application.Billing.CancelPaymentRequest;
+using PnvPanel.Application.Billing.CreatePaymentRequest;
+using PnvPanel.Application.Billing.GetMyBillingStatus;
+using PnvPanel.Application.Billing.MarkPaymentSent;
+using PnvPanel.Application.Billing.SendRequisitesToTelegram;
+using PnvPanel.Application.Common.Messaging;
+using PnvPanel.Domain.Billing;
+
+namespace PnvPanel.Api.Endpoints;
+
+public static class BillingEndpoints
+{
+    public static IEndpointRouteBuilder MapBillingEndpoints(this IEndpointRouteBuilder app)
+    {
+        var group = app.MapGroup("/api/billing").WithTags("Billing").RequireAuthorization();
+
+        group.MapGet("/status", GetStatus).Produces<BillingStatusDto>();
+        group.MapPost("/requests", CreateRequest).Produces<PaymentRequestDto>();
+        group
+            .MapPost("/requests/{id:guid}/cancel", CancelRequest)
+            .Produces(StatusCodes.Status204NoContent);
+        group
+            .MapPost("/requests/{id:guid}/mark-paid", MarkPaid)
+            .Produces(StatusCodes.Status204NoContent);
+        group
+            .MapPost("/requests/{id:guid}/send-requisites", SendRequisites)
+            .Produces(StatusCodes.Status204NoContent);
+
+        return app;
+    }
+
+    private static async Task<IResult> GetStatus(ISender sender, CancellationToken cancellationToken)
+    {
+        var result = await sender.Send(new GetMyBillingStatusQuery(), cancellationToken);
+        return result.ToHttpResult();
+    }
+
+    private static async Task<IResult> CreateRequest(
+        CreatePaymentRequestBody body,
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var result = await sender.Send(
+            new CreatePaymentRequestCommand(body.Period),
+            cancellationToken
+        );
+        return result.ToHttpResult();
+    }
+
+    private static async Task<IResult> CancelRequest(
+        Guid id,
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var result = await sender.Send(new CancelPaymentRequestCommand(id), cancellationToken);
+        return result.ToHttpResult();
+    }
+
+    private static async Task<IResult> MarkPaid(
+        Guid id,
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var result = await sender.Send(new MarkPaymentSentCommand(id), cancellationToken);
+        return result.ToHttpResult();
+    }
+
+    private static async Task<IResult> SendRequisites(
+        Guid id,
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var result = await sender.Send(new SendRequisitesToTelegramCommand(id), cancellationToken);
+        return result.ToHttpResult();
+    }
+}
+
+public sealed record CreatePaymentRequestBody(PaymentPeriod Period);

backend/src/PnvPanel.Api/Endpoints/RoleEndpoints.cs

@@ -53,7 +53,7 @@ public static class RoleEndpoints
     )
     {
         var result = await sender.Send(
-            new UpdateRoleCommand(id, body.MaxConfigs, body.MaxIpLimit),
+            new UpdateRoleCommand(id, body.MaxConfigs, body.MaxIpLimit, body.BillingEnabled),
             cancellationToken
         );
         return result.ToHttpResult();
@@ -84,6 +84,6 @@ public static class RoleEndpoints
     }
 }
 
-public sealed record UpdateRoleBody(int MaxConfigs, int MaxIpLimit);
+public sealed record UpdateRoleBody(int MaxConfigs, int MaxIpLimit, bool BillingEnabled);
 
 public sealed record ChangeUserRoleBody(Guid RoleId);

backend/src/PnvPanel.Api/Program.cs

@@ -192,6 +192,8 @@ app.MapAdminAppEndpoints();
 app.MapAdminNewsEndpoints();
 app.MapAdminInstructionEndpoints();
 app.MapAdminPricingEndpoints();
+app.MapBillingEndpoints();
+app.MapAdminBillingEndpoints();
 app.MapSupportEndpoints();
 app.MapAdminSupportEndpoints();
 app.MapAdminMaintenanceEndpoints();

backend/src/PnvPanel.Api/Telegram/PnvBotUpdateHandler.cs

@@ -1,5 +1,6 @@
 using Microsoft.Extensions.Options;
 using PnvPanel.Application.Admin.Activation;
+using PnvPanel.Application.Admin.Billing;
 using PnvPanel.Application.Admin.Support;
 using PnvPanel.Application.Common.Interfaces;
 using PnvPanel.Application.Common.Messaging;
@@ -442,6 +443,55 @@ public sealed class PnvBotUpdateHandler(
 
                 break;
             }
+            case "pay":
+            {
+                if (!await TrySetAdminCurrentUserAsync(services, fromId, cancellationToken))
+                {
+                    await botClient.AnswerCallbackQuery(
+                        callback.Id,
+                        "Недостаточно прав.",
+                        cancellationToken: cancellationToken
+                    );
+                    return;
+                }
+
+                var result =
+                    parts[1] == "approve"
+                        ? await sender.Send(
+                            new ConfirmPaymentRequestCommand(requestId),
+                            cancellationToken
+                        )
+                        : await sender.Send(
+                            new RejectPaymentRequestCommand(requestId, Reason: null),
+                            cancellationToken
+                        );
+
+                await botClient.AnswerCallbackQuery(
+                    callback.Id,
+                    result.IsSuccess ? "Готово" : result.Error.Message,
+                    cancellationToken: cancellationToken
+                );
+                if (callback.Message is not null)
+                {
+                    var statusText = result.IsSuccess
+                        ? (
+                            parts[1] == "approve"
+                                ? "✅ Оплата подтверждена."
+                                : "❌ Оплата отклонена."
+                        )
+                        : $"⚠️ {result.Error.Message}";
+                    var text = $"{Escape(callback.Message.Text ?? "")}\n\n{statusText}";
+                    await botClient.EditMessageText(
+                        chatId.Value,
+                        callback.Message.Id,
+                        text,
+                        parseMode: ParseMode.Html,
+                        cancellationToken: cancellationToken
+                    );
+                }
+
+                break;
+            }
             case "cfg":
             {
                 if (!await TrySetCurrentUserAsync(services, fromId, cancellationToken))

backend/src/PnvPanel.Api/Telegram/TelegramNotifier.cs

@@ -1,5 +1,6 @@
 using Microsoft.Extensions.Options;
 using PnvPanel.Application.Common.Interfaces;
+using PnvPanel.Domain.Billing;
 using PnvPanel.Domain.Support;
 using PnvPanel.Infrastructure.Telegram;
 using Telegram.Bot;
@@ -225,6 +226,56 @@ internal sealed class TelegramNotifier(
         }
     }
 
+    public async Task NotifyAdminsPaymentRequestedAsync(
+        Guid requestId,
+        string userName,
+        PaymentPeriod period,
+        int amount,
+        CancellationToken cancellationToken
+    )
+    {
+        if (string.IsNullOrWhiteSpace(options.Value.BotToken))
+            return;
+
+        var text =
+            $"💰 <b>{Escape(userName)}</b> заявляет об оплате за {PeriodLabel(period)} — {amount} ₽\nПроверьте поступление и подтвердите.";
+
+        var keyboard = new InlineKeyboardMarkup(
+            new[]
+            {
+                InlineKeyboardButton.WithCallbackData("✅ Подтвердить", $"pay:approve:{requestId}"),
+                InlineKeyboardButton.WithCallbackData("❌ Отклонить", $"pay:reject:{requestId}"),
+            }
+        );
+
+        foreach (var adminId in options.Value.ParseAdminTelegramUserIds())
+        {
+            try
+            {
+                await botClient.SendMessage(
+                    adminId,
+                    text,
+                    parseMode: ParseMode.Html,
+                    replyMarkup: keyboard,
+                    cancellationToken: cancellationToken
+                );
+            }
+            catch
+            {
+                // Админ мог не запускать бота (нет чата с ботом) — пропускаем, не валим команду.
+            }
+        }
+    }
+
+    private static string PeriodLabel(PaymentPeriod period) =>
+        period switch
+        {
+            PaymentPeriod.Quarter => "3 месяца",
+            PaymentPeriod.HalfYear => "полгода",
+            PaymentPeriod.Year => "год",
+            _ => period.ToString(),
+        };
+
     public async Task NotifyUserAsync(
         Guid userId,
         string message,