ci: consolidate platform pipelines and test prerequisites on macOS support

MeetingAssistant.Tests/MeetingWorkflowDiagnosticEndpointTests.cs

@@ -1,7 +1,6 @@
 using System.Net;
 using System.Net.Http.Json;
 using System.Text.Json;
-using Microsoft.AspNetCore.Mvc.Testing;
 using Microsoft.Extensions.Configuration;
 
 namespace MeetingAssistant.Tests;
@@ -17,7 +16,7 @@ public sealed class MeetingWorkflowDiagnosticEndpointTests
         var firstRulesPath = Path.Combine(root, "first-rules.yaml");
         var secondRulesPath = Path.Combine(root, "second-rules.yaml");
         await File.WriteAllTextAsync(configPath, CreateConfigJson(firstRulesPath));
-        await using var factory = new WebApplicationFactory<Program>()
+        await using var factory = new IsolatedApplicationFactory()
             .WithWebHostBuilder(builder =>
             {
                 builder.ConfigureAppConfiguration((_, configuration) =>