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/Common/Interfaces/IAppDbContext.cs

@@ -0,0 +1,11 @@
+using Microsoft.EntityFrameworkCore;
+using TeleWave.Domain.Auth;
+
+namespace TeleWave.Application.Common.Interfaces;
+
+public interface IAppDbContext
+{
+    DbSet<RefreshToken> RefreshTokens { get; }
+
+    Task<int> SaveChangesAsync(CancellationToken cancellationToken);
+}