Refactor ActionController to use MediatR

Updated `using` directives to include MediatR and related namespaces. Refactored `ActionController` to use constructor injection for `IMediator`. Modified the `Invoke` method to be asynchronous and replaced the placeholder `NotImplementedException` with a call to `mediator.InvokeRecAction(profileId)`. The method now returns an `Accepted` HTTP response to indicate successful request processing.

src/ReC.API/Controllers/ActionController.cs

@@ -1,15 +1,17 @@
-using Microsoft.AspNetCore.Mvc;
+using MediatR;
+using Microsoft.AspNetCore.Mvc;
+using ReC.Application.RecActions.Commands;
 
 namespace ReC.API.Controllers;
 
 [Route("api/[controller]")]
 [ApiController]
-public class ActionController : ControllerBase
+public class ActionController(IMediator mediator) : ControllerBase
 {
     [HttpPost("{profileId}")]
-    public Task<IActionResult> Invoke([FromRoute] int profileId)
+    public async Task<IActionResult> Invoke([FromRoute] int profileId)
     {
-        // Implementation for retrieving actions would go here.
-        throw new NotImplementedException();
+        await mediator.InvokeRecAction(profileId);
+        return Accepted();
     }
 }