Add settings endpoints and registration status check: implement new API endpoints for settings management, including registration status retrieval, and update the registration command handler to enforce registration rules based on site settings.

backend/src/TeleWave.Api/Endpoints/AuthEndpoints.cs

@@ -9,6 +9,7 @@ using TeleWave.Application.Auth.Logout;
 using TeleWave.Application.Auth.Me;
 using TeleWave.Application.Auth.Refresh;
 using TeleWave.Application.Auth.Register;
+using TeleWave.Application.Settings.GetSiteSettings;
 
 namespace TeleWave.Api.Endpoints;
 
@@ -22,6 +23,7 @@ public static class AuthEndpoints
             .WithTags("Auth")
             .RequireRateLimiting(RateLimiting.AuthPolicy);
 
+        group.MapGet("/registration", RegistrationStatus).Produces<RegistrationStatusDto>();
         group.MapPost("/register", Register).Produces<AuthResponseDto>();
         group.MapPost("/login", Login).Produces<AuthResponseDto>();
         group.MapPost("/refresh", Refresh).Produces<AuthResponseDto>();
@@ -46,6 +48,15 @@ public static class AuthEndpoints
         return app;
     }
 
+    private static async Task<IResult> RegistrationStatus(
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var settings = await sender.Send(new GetSiteSettingsQuery(), cancellationToken);
+        return Results.Ok(new RegistrationStatusDto(settings.RegistrationEnabled));
+    }
+
     private static async Task<IResult> Register(
         RegisterCommand command,
         ISender sender,
@@ -218,3 +229,6 @@ public sealed record AuthResponseDto(
     DateTimeOffset ExpiresAt,
     CurrentUserDto User
 );
+
+/// <summary>Публичный ответ: включена ли открытая регистрация (для страниц входа/регистрации).</summary>
+public sealed record RegistrationStatusDto(bool Enabled);