Enhance user plan management and update related endpoints

- Added new configuration options for user plans in `.env.example`, including `Plans__MaxCustomConfigCount` and `Plans__MinCustomConfigCount`.
- Introduced `MapPlanEndpoints` in `Program.cs` to handle plan-related API routes.
- Implemented `SetUserPlan` endpoint in `RoleEndpoints` to allow admins to assign plans to users.
- Removed deprecated role request approval endpoints from `AdminSupportEndpoints`.
- Updated `ITelegramNotifier` and related classes to reflect changes in role request handling and payment notifications.
- Refactored role management commands to remove `MaxConfigs` and focus on `MaxIpLimit` and billing settings.
- Enhanced billing request handling to accommodate plan changes instead of role changes.
- Updated various interfaces and command handlers to support new plan management features.

backend/tests/PnvPanel.Application.Tests/Admin/Users/ListUsersQueryHandlerTests.cs

@@ -56,13 +56,13 @@ public class ListUsersQueryHandlerTests
     }
 
     [Fact]
-    public async Task Handle_WhenPendingRequestIsRoleChangeTopUp_LeavesBillingPendingReviewFalse()
+    public async Task Handle_WhenPendingRequestIsPlanChangeTopUp_LeavesBillingPendingReviewFalse()
     {
-        // RoleChangeTopUp — доплата за смену роли, не подписка; не должна показывать пользователя
+        // PlanChangeTopUp — доплата за смену тарифа, не подписка; не должна показывать пользователя
         // как "оплата на проверке" в админке (см. CLAUDE.md про Kind).
         using var dbContext = InMemoryDbContextFactory.Create();
         var userId = Guid.NewGuid();
-        var request = PaymentRequest.CreateRoleChangeTopUp(userId, 500);
+        var request = PaymentRequest.CreatePlanChangeTopUp(userId, 500);
         request.MarkPaymentSent();
         dbContext.PaymentRequests.Add(request);
         await dbContext.SaveChangesAsync(CancellationToken.None);