feat: Add Windows Service hosting support

- Add Microsoft.Extensions.Hosting.WindowsServices package
- Add HostingOptions:UseWindowsService configuration flag to appsettings.json
- Configure Program.cs to optionally run as Windows Service based on config
- IIS hosting continues to work by default (UseWindowsService=false)
- Delete obsolete Worker.cs that was conflicting with ProfileManager

ECMJobRunner.WebCron/Program.cs

@@ -7,6 +7,12 @@ using Microsoft.Data.SqlClient;
 
 var builder = WebApplication.CreateBuilder(args);
 
+// Configure Windows Service hosting if enabled
+if (builder.Configuration.GetValue<bool>("HostingOptions:UseWindowsService"))
+{
+    builder.Host.UseWindowsService();
+}
+
 // Add services to the container.
 builder.Services.AddControllers();
 builder.Services.AddHostedService<ProfileManager>();