`WithExplicitStart()` should block `OnBeforeResourceStarted`

[afscrome]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

If you have a resource WithExplicitStart() and with OnBeforeResourceStarted(), the event will fire on app start up, even if you haven't explicitly triggered the resource to start.

The event will then fire a second time (and a third time due to #13068) when you actually start the resource.

Expected Behavior

The event should only fire once (not 3 times), and I'd expect the event to not fire until after the resource is explicitly started.

Steps To Reproduce

var builder = DistributedApplication
    .CreateBuilder(args);

var foo = builder.AddContainer("nginx", "nginx")
    .WithExplicitStart()
    .OnBeforeResourceStarted((_, _, _) =>
    {
        Console.WriteLine($"Before Start {DateTime.Now}");
        return Task.CompletedTask;
    });

builder.Build().Run();

Exceptions (if any)

info: Aspire.Hosting.DistributedApplication[0]
      Aspire version: 13.0.0+7512c2944094a58904b6c803aa824c4a4ce42e11
info: Aspire.Hosting.DistributedApplication[0]
      Distributed application starting.
info: Aspire.Hosting.DistributedApplication[0]
      Application host directory is: S:\DotNetConf\DotNetConf.AppHost
Before Start 20/11/2025 14:05:23
info: Aspire.Hosting.DistributedApplication[0]
      Distributed application started. Press Ctrl+C to shut down.
info: Aspire.Hosting.DistributedApplication[0]
      Now listening on: https://localhost:17031
info: Aspire.Hosting.DistributedApplication[0]
      Login to the dashboard at https://localhost:17031/login?t=db417f7470e0d14fdebe82c268787cf5
Before Start 20/11/2025 14:05:32
Before Start 20/11/2025 14:05:32

.NET Version info

No response

Anything else?

No response