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/src/TeleWave.Application/Admin/Users/BlockUser/BlockUserCommandHandler.cs

@@ -0,0 +1,19 @@
+using LiteCqrs;
+using TeleWave.Application.Common.Interfaces;
+using TeleWave.Application.Common.Models;
+
+namespace TeleWave.Application.Admin.Users.BlockUser;
+
+public sealed class BlockUserCommandHandler(
+    IIdentityService identityService,
+    ICurrentUser currentUser
+) : ICommandHandler<BlockUserCommand, Result>
+{
+    public Task<Result> Handle(BlockUserCommand command, CancellationToken cancellationToken)
+    {
+        if (currentUser.UserId == command.UserId)
+            return Task.FromResult(Result.Failure(UserErrors.CannotBlockSelf));
+
+        return identityService.BlockUserAsync(command.UserId, cancellationToken);
+    }
+}