Update single-file AppHost template with complete SDK directives

Co-authored-by: mitchdenny <[email protected]>

Author: Copilot

src/Aspire.ProjectTemplates/templates/aspire-apphost-singlefile/9.5/apphost.cs

@@ -1,4 +1,7 @@
+#:sdk Microsoft.NET.Sdk
 #:sdk Aspire.AppHost.Sdk@aspireVersion
+#:package Aspire.Hosting.AppHost@aspireVersion
+#:property PublishAot=false
 
 var builder = DistributedApplication.CreateBuilder(args);