Initial commit: base slice (auth, roles, users, admin) scaffold

Backend: .NET 10 Clean Architecture + LiteCqrs.Net + EF Core/PostgreSQL +
Identity/JWT. Frontend: React 19 + Vite + TanStack Query/Router + Tailwind v4
with a retro CRT theme. Docker/compose deployment mirroring PnvPanel's
conventions, scoped down to the current base feature set.

backend/tests/TeleWave.Application.Tests/Admin/Users/BlockUserCommandHandlerTests.cs

@@ -0,0 +1,45 @@
+using NSubstitute;
+using TeleWave.Application.Admin.Users;
+using TeleWave.Application.Admin.Users.BlockUser;
+using TeleWave.Application.Common.Interfaces;
+using TeleWave.Application.Common.Models;
+using Xunit;
+
+namespace TeleWave.Application.Tests.Admin.Users;
+
+public class BlockUserCommandHandlerTests
+{
+    private readonly IIdentityService _identityService = Substitute.For<IIdentityService>();
+    private readonly ICurrentUser _currentUser = Substitute.For<ICurrentUser>();
+
+    private BlockUserCommandHandler CreateHandler() => new(_identityService, _currentUser);
+
+    [Fact]
+    public async Task Handle_WhenTargetingSelf_ReturnsFailureWithoutCallingIdentityService()
+    {
+        var userId = Guid.NewGuid();
+        _currentUser.UserId.Returns(userId);
+
+        var result = await CreateHandler().Handle(new BlockUserCommand(userId), CancellationToken.None);
+
+        Assert.False(result.IsSuccess);
+        Assert.Equal(UserErrors.CannotBlockSelf, result.Error);
+        await _identityService.DidNotReceive().BlockUserAsync(Arg.Any<Guid>(), Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_WhenTargetingAnotherUser_DelegatesToIdentityService()
+    {
+        var adminId = Guid.NewGuid();
+        var targetId = Guid.NewGuid();
+        _currentUser.UserId.Returns(adminId);
+        _identityService
+            .BlockUserAsync(targetId, Arg.Any<CancellationToken>())
+            .Returns(Result.Success());
+
+        var result = await CreateHandler().Handle(new BlockUserCommand(targetId), CancellationToken.None);
+
+        Assert.True(result.IsSuccess);
+        await _identityService.Received(1).BlockUserAsync(targetId, Arg.Any<CancellationToken>());
+    }
+}