fix(service): Clear SQLite connection pools on service stop

Should fix manual delete of Regression tests which create a temp SQLite DB for their tests.

server/RdtClient.Service/BackgroundServices/Startup.cs

@@ -1,4 +1,5 @@
 using System.Reflection;
+using Microsoft.Data.Sqlite;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
@@ -39,6 +40,9 @@ public class Startup(IServiceProvider serviceProvider) : IHostedService
 
     public Task StopAsync(CancellationToken cancellationToken)
     {
+        Ready = false;
+        SqliteConnection.ClearAllPools();
+
         return Task.CompletedTask;
     }
 }