Require non-null References for batch rec action invoke

Enforce non-nullable References in RecActionController and InvokeBatchRecActionViewsCommand. Update tests to always provide References and add missing using directive. Improves type safety and ensures consistent reference handling.

src/ReC.API/Controllers/RecActionController.cs

@@ -19,7 +19,7 @@ public class RecActionController(IMediator mediator) : ControllerBase
     /// <returns>An HTTP 202 Accepted response indicating the process has been started.</returns>
     [HttpPost("invoke/{profileId}")]
     [ProducesResponseType(StatusCodes.Status202Accepted)]
-    public async Task<IActionResult> Invoke([FromRoute] long profileId, [FromBody] InvokeReferences? references = null, CancellationToken cancel = default)
+    public async Task<IActionResult> Invoke([FromRoute] long profileId, [FromBody] InvokeReferences references, CancellationToken cancel = default)
     {
         await mediator.Send(new InvokeBatchRecActionViewsCommand
         {

src/ReC.Application/RecActions/Commands/InvokeBatchRecActionViewsCommand.cs

@@ -9,7 +9,7 @@ namespace ReC.Application.RecActions.Commands;
 public record InvokeBatchRecActionViewsCommand : IRequest
 {
     public long ProfileId { get; init; }
-    public InvokeReferences? References { get; init; }
+    public required InvokeReferences References { get; init; }
 }
 
 public class InvokeRecActionViewsCommandHandler(ISender sender, ILogger<InvokeRecActionViewsCommandHandler>? logger = null) : IRequestHandler<InvokeBatchRecActionViewsCommand>