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/Models/Error.cs

@@ -0,0 +1,34 @@
+namespace TeleWave.Application.Common.Models;
+
+public enum ErrorType
+{
+    Failure,
+    Validation,
+    NotFound,
+    Conflict,
+    Unauthorized,
+    Forbidden,
+}
+
+public sealed record Error(string Code, string Message, ErrorType Type = ErrorType.Failure)
+{
+    public static readonly Error None = new(string.Empty, string.Empty);
+
+    public static Error Validation(string code, string message) =>
+        new(code, message, ErrorType.Validation);
+
+    public static Error NotFound(string code, string message) =>
+        new(code, message, ErrorType.NotFound);
+
+    public static Error Conflict(string code, string message) =>
+        new(code, message, ErrorType.Conflict);
+
+    public static Error Unauthorized(string code, string message) =>
+        new(code, message, ErrorType.Unauthorized);
+
+    public static Error Forbidden(string code, string message) =>
+        new(code, message, ErrorType.Forbidden);
+
+    public static Error Failure(string code, string message) =>
+        new(code, message, ErrorType.Failure);
+}

backend/src/TeleWave.Application/Common/Models/PagedList.cs

@@ -0,0 +1,3 @@
+namespace TeleWave.Application.Common.Models;
+
+public sealed record PagedList<T>(IReadOnlyList<T> Items, int Total, int Page, int PageSize);

backend/src/TeleWave.Application/Common/Models/Result.cs

@@ -0,0 +1,43 @@
+namespace TeleWave.Application.Common.Models;
+
+public class Result
+{
+    public bool IsSuccess { get; }
+    public Error Error { get; }
+
+    protected Result(bool isSuccess, Error error)
+    {
+        if (isSuccess && error != Error.None)
+            throw new InvalidOperationException("Успешный результат не может содержать ошибку.");
+        if (!isSuccess && error == Error.None)
+            throw new InvalidOperationException("Неуспешный результат обязан содержать ошибку.");
+
+        IsSuccess = isSuccess;
+        Error = error;
+    }
+
+    public static Result Success() => new(true, Error.None);
+
+    public static Result Failure(Error error) => new(false, error);
+
+    public static Result<T> Success<T>(T value) => new(value, true, Error.None);
+
+    public static Result<T> Failure<T>(Error error) => new(default, false, error);
+}
+
+public class Result<T> : Result
+{
+    private readonly T? _value;
+
+    internal Result(T? value, bool isSuccess, Error error)
+        : base(isSuccess, error) => _value = value;
+
+    public T Value =>
+        IsSuccess
+            ? _value!
+            : throw new InvalidOperationException(
+                "Нельзя получить значение неуспешного результата."
+            );
+
+    public static implicit operator Result<T>(T value) => Success(value);
+}