do sessions in memory and also fix glaring security hole

Femto.Modules.Auth/Application/Interface/GetUserInfo/GetUserInfoCommandHandler.cs

@@ -0,0 +1,27 @@
+using Femto.Common.Domain;
+using Femto.Modules.Auth.Application.Dto;
+using Femto.Modules.Auth.Data;
+using Microsoft.EntityFrameworkCore;
+
+namespace Femto.Modules.Auth.Application.Interface.GetUserInfo;
+
+internal class GetUserInfoCommandHandler(AuthContext context)
+    : ICommandHandler<GetUserInfoCommand, UserInfo?>
+{
+    public async Task<UserInfo?> Handle(
+        GetUserInfoCommand request,
+        CancellationToken cancellationToken
+    )
+    {
+
+        var user = await context.Users.SingleOrDefaultAsync(
+            u => u.Id == request.ForUser,
+            cancellationToken
+        );
+
+        if (user is null)
+            return null;
+
+        return new UserInfo(user);
+    }
+}