Set AddedWho from config in Create; make property mutable

Changed AuthScope.AddedWho to be mutable (get; set;). In ResultViewController, set AddedWho from configuration in the Create action and throw an error if missing. Ensures AddedWho is always set and configuration issues are clearly reported.

src/ReC.API/Controllers/ResultViewController.cs

@@ -43,6 +43,8 @@ public class ResultViewController(IMediator mediator, IConfiguration config) : C
     [HttpPost]
     public async Task<IActionResult> Create([FromBody] CreateResultViewCommand command, CancellationToken cancel)
     {
+        // TODO: add middleware
+        command.Scope.AddedWho = config?["AddedWho"] ?? throw new InvalidOperationException("The required 'AddedWho' configuration is missing. Please contact a system administrator.");
         await mediator.Send(command, cancel);
         return CreatedAtAction(nameof(Get), new { actionId = command.ActionId }, command);
     }

src/ReC.Application/Common/Interfaces/IAuthScoped.cs

@@ -4,7 +4,7 @@ namespace ReC.Application.Common.Interfaces;
 
 public record AuthScope
 {
-    public string AddedWho { get; } = null!;
+    public string AddedWho { get; set; } = null!;
 }
 
 public interface IAuthScoped : IScoped<AuthScope>