Enhance API endpoints with response type annotations

- Updated various API endpoints to include response type annotations using .Produces<T>() for better documentation and type safety.
- Enhanced activation, admin, user, config, and other endpoints to specify response types, improving clarity for frontend integration.
- Added new DTOs for structured responses in authentication and Telegram-related endpoints.
- Improved overall API schema generation to reflect these changes, ensuring consistency between backend and frontend types.

backend/src/PnvPanel.Api/Endpoints/RoleEndpoints.cs

@@ -1,6 +1,7 @@
 using PnvPanel.Api.Common;
 using PnvPanel.Application.Admin.Roles;
 using PnvPanel.Application.Admin.Users;
+using PnvPanel.Application.Common.Interfaces;
 using PnvPanel.Application.Common.Messaging;
 using PnvPanel.Infrastructure.Identity;
 
@@ -14,11 +15,11 @@ public static class RoleEndpoints
             .WithTags("Admin.Roles")
             .RequireAuthorization(policy => policy.RequireRole(RoleNames.Admin));
 
-        admin.MapGet("/roles", ListRoles);
-        admin.MapPost("/roles", CreateRole);
-        admin.MapPut("/roles/{id:guid}", UpdateRole);
-        admin.MapDelete("/roles/{id:guid}", DeleteRole);
-        admin.MapPatch("/users/{id:guid}/role", ChangeUserRole);
+        admin.MapGet("/roles", ListRoles).Produces<IReadOnlyList<RoleDto>>();
+        admin.MapPost("/roles", CreateRole).Produces<RoleDto>();
+        admin.MapPut("/roles/{id:guid}", UpdateRole).Produces<RoleDto>();
+        admin.MapDelete("/roles/{id:guid}", DeleteRole).Produces(StatusCodes.Status204NoContent);
+        admin.MapPatch("/users/{id:guid}/role", ChangeUserRole).Produces(StatusCodes.Status204NoContent);
 
         return app;
     }