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/UserErrors.cs

@@ -0,0 +1,18 @@
+using TeleWave.Application.Common.Models;
+
+namespace TeleWave.Application.Admin.Users;
+
+public static class UserErrors
+{
+    public static readonly Error NotFound = Error.NotFound("Users.NotFound", "Пользователь не найден.");
+
+    public static readonly Error CannotDeleteSelf = Error.Forbidden(
+        "Users.CannotDeleteSelf",
+        "Нельзя удалить собственный аккаунт через админку."
+    );
+
+    public static readonly Error CannotBlockSelf = Error.Forbidden(
+        "Users.CannotBlockSelf",
+        "Нельзя заблокировать собственный аккаунт."
+    );
+}