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.IntegrationTests/Configs/ConfigQuotaTests.cs

@@ -11,7 +11,7 @@ public class ConfigQuotaTests(PnvPanelWebApplicationFactory factory)
     private const int Quota = 2;
     private const int ConcurrentAttempts = 6;
 
-    private sealed record RoleResponse(Guid Id, string Name, int MaxConfigs, bool IsSystem);
+    private sealed record RoleResponse(Guid Id, string Name, bool IsSystem);
 
     private sealed record NodeResponse(Guid Id, string Name);
 
@@ -33,7 +33,7 @@ public class ConfigQuotaTests(PnvPanelWebApplicationFactory factory)
         DateTimeOffset CreatedAt
     );
 
-    private sealed record MyConfigsResponse(List<object> Configs, int MaxConfigs);
+    private sealed record MyConfigsResponse(List<object> Configs, int ConfigQuota);
 
     /// <summary>
     /// Доказывает, что pg_advisory_xact_lock в CreateVpnConfigCommandHandler реально защищает
@@ -54,7 +54,7 @@ public class ConfigQuotaTests(PnvPanelWebApplicationFactory factory)
 
         var updateRoleResponse = await adminClient.SendPutJsonAsync(
             $"/api/admin/roles/{userRole.Id}",
-            new { maxConfigs = Quota, maxIpLimit = -1 }
+            new { maxIpLimit = -1, billingEnabled = false }
         );
         Assert.Equal(HttpStatusCode.OK, updateRoleResponse.StatusCode);
 
@@ -109,6 +109,13 @@ public class ConfigQuotaTests(PnvPanelWebApplicationFactory factory)
         );
         Assert.Equal(HttpStatusCode.NoContent, approveResponse.StatusCode);
 
+        // Квота конфигов больше не на роли — пользователь сам выбирает тариф (см. ChangePlanCommand).
+        var changePlanResponse = await userClient.PostJsonAsync(
+            "/api/plans/change",
+            new { customConfigCount = Quota, configIdsToRevoke = Array.Empty<Guid>() }
+        );
+        Assert.Equal(HttpStatusCode.OK, changePlanResponse.StatusCode);
+
         var tasks = Enumerable
             .Range(0, ConcurrentAttempts)
             .Select(async i =>