Implement support ticket system with role request and bug report functionalities

- Introduced a new support ticket system allowing users to submit bug reports and role requests.
- Implemented endpoints for creating, updating, and managing support tickets, including file attachments.
- Enhanced Telegram bot integration to handle role requests directly within the bot, enabling admins to approve or reject requests without accessing the website.
- Updated database schema to include support ticket entities and their relationships.
- Improved API documentation to reflect new support ticket endpoints and their usage.
- Added necessary localization for support ticket features in both Russian and English.

backend/tests/PnvPanel.Application.Tests/Support/CreateRoleRequestTicketCommandHandlerTests.cs

@@ -0,0 +1,92 @@
+using NSubstitute;
+using PnvPanel.Application.Common.Interfaces;
+using PnvPanel.Application.Support;
+using PnvPanel.Application.Support.CreateRoleRequest;
+using PnvPanel.Application.Tests.TestSupport;
+using PnvPanel.Domain.Support;
+using Xunit;
+
+namespace PnvPanel.Application.Tests.Support;
+
+public class CreateRoleRequestTicketCommandHandlerTests
+{
+    private readonly IRoleService _roleService = Substitute.For<IRoleService>();
+    private readonly IRealtimeNotifier _notifier = Substitute.For<IRealtimeNotifier>();
+    private readonly ITelegramNotifier _telegramNotifier = Substitute.For<ITelegramNotifier>();
+
+    [Fact]
+    public async Task Handle_ForExistingRole_CreatesTicket()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var userId = Guid.NewGuid();
+        var roleId = Guid.NewGuid();
+        var currentUser = FakeCurrentUser.Authenticated(userId, "alice");
+        _roleService.ListRolesAsync(Arg.Any<CancellationToken>())
+            .Returns(new List<RoleDto> { new(roleId, "premium", 5, 2, false) });
+
+        var handler = new CreateRoleRequestTicketCommandHandler(dbContext, _roleService, _notifier, _telegramNotifier, currentUser);
+
+        var result = await handler.Handle(
+            new CreateRoleRequestTicketCommand(roleId, null, null, null, "нужно больше конфигов"), CancellationToken.None);
+        await dbContext.SaveChangesAsync(CancellationToken.None);
+
+        Assert.True(result.IsSuccess);
+        Assert.Equal(roleId, result.Value.RequestedRoleId);
+        Assert.Equal("premium", result.Value.RequestedRoleName);
+        await _telegramNotifier.Received(1).NotifyAdminsRoleRequestCreatedAsync(
+            Arg.Any<Guid>(), "alice", "premium", "нужно больше конфигов", Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_ForAdminRole_ReturnsForbidden()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var roleId = Guid.NewGuid();
+        var currentUser = FakeCurrentUser.Authenticated(Guid.NewGuid());
+        _roleService.ListRolesAsync(Arg.Any<CancellationToken>())
+            .Returns(new List<RoleDto> { new(roleId, "admin", -1, -1, true) });
+
+        var handler = new CreateRoleRequestTicketCommandHandler(dbContext, _roleService, _notifier, _telegramNotifier, currentUser);
+
+        var result = await handler.Handle(
+            new CreateRoleRequestTicketCommand(roleId, null, null, null, "хочу быть админом"), CancellationToken.None);
+
+        Assert.False(result.IsSuccess);
+        Assert.Equal(SupportErrors.CannotRequestAdminRole, result.Error);
+    }
+
+    [Fact]
+    public async Task Handle_ForNewRole_SetsProposedFields()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var currentUser = FakeCurrentUser.Authenticated(Guid.NewGuid(), "bob");
+
+        var handler = new CreateRoleRequestTicketCommandHandler(dbContext, _roleService, _notifier, _telegramNotifier, currentUser);
+
+        var result = await handler.Handle(
+            new CreateRoleRequestTicketCommand(null, "custom", 10, 4, "нужна кастомная роль"), CancellationToken.None);
+
+        Assert.True(result.IsSuccess);
+        Assert.Equal("custom", result.Value.ProposedRoleName);
+        Assert.Equal(10, result.Value.ProposedMaxConfigs);
+        Assert.Equal(4, result.Value.ProposedMaxIpLimit);
+    }
+
+    [Fact]
+    public async Task Handle_WhenPendingRoleRequestExists_ReturnsConflict()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var userId = Guid.NewGuid();
+        dbContext.SupportTickets.Add(SupportTicket.CreateRoleRequestForNewRole(userId, "x", 1, 1));
+        await dbContext.SaveChangesAsync(CancellationToken.None);
+
+        var currentUser = FakeCurrentUser.Authenticated(userId);
+        var handler = new CreateRoleRequestTicketCommandHandler(dbContext, _roleService, _notifier, _telegramNotifier, currentUser);
+
+        var result = await handler.Handle(
+            new CreateRoleRequestTicketCommand(null, "y", 2, 2, "ещё заявка"), CancellationToken.None);
+
+        Assert.False(result.IsSuccess);
+        Assert.Equal(SupportErrors.RoleRequestAlreadyPending, result.Error);
+    }
+}