Add http health check for Angular app

To have a better indication in the dashboard as to when the app has
actually started, because the dashboard otherwise displays a running
state after the launch command has been given, but then the app only
begins to compile and takes a few seconds to actually launch

src/Vegasco.Server.AppHost/Program.cs

@@ -17,6 +17,7 @@ builder
 	.WithReference(api)
 	.WaitFor(api)
 	.WithHttpEndpoint(port: 44200, env: "PORT", isProxied: false)
-	.WithExternalHttpEndpoints();
+	.WithExternalHttpEndpoints()
+	.WithHttpHealthCheck("/", 200);
 
 builder.Build().Run();