Update .gitignore to exclude TypeScript build info and add dist directory. Expand README with project overview, technology stack, prerequisites, and instructions for running and testing the application.

tests/HSchool.AppHost.Tests/AppHostFixture.cs

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+using Microsoft.Extensions.Logging;
+
+namespace HSchool.AppHost.Tests;
+
+/// <summary>
+/// Boots the AppHost once for the whole suite — starting it per test costs about ten
+/// seconds each. The client resource is skipped (<c>HSchool:Headless</c>), so the tests
+/// need no Node install.
+/// </summary>
+public sealed class AppHostFixture : IAsyncLifetime
+{
+    private static readonly TimeSpan StartupTimeout = TimeSpan.FromSeconds(120);
+
+    private DistributedApplication? _app;
+
+    public DistributedApplication App =>
+        _app ?? throw new InvalidOperationException("The AppHost has not been started.");
+
+    public async ValueTask InitializeAsync()
+    {
+        var appHost = await DistributedApplicationTestingBuilder
+            .CreateAsync<Projects.HSchool_AppHost>(["--HSchool:Headless=true"], CancellationToken.None);
+
+        appHost.Services.AddLogging(logging =>
+        {
+            logging.SetMinimumLevel(LogLevel.Warning);
+            logging.AddFilter("Aspire.", LogLevel.Warning);
+        });
+
+        _app = await appHost.BuildAsync().WaitAsync(StartupTimeout);
+        await _app.StartAsync().WaitAsync(StartupTimeout);
+        await _app.ResourceNotifications
+            .WaitForResourceHealthyAsync("server", CancellationToken.None)
+            .WaitAsync(StartupTimeout);
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_app is not null)
+        {
+            await _app.DisposeAsync();
+        }
+    }
+}
+
+/// <summary>Groups every integration test around the single AppHost instance.</summary>
+[CollectionDefinition(Name)]
+public sealed class AppHostCollection : ICollectionFixture<AppHostFixture>
+{
+    public const string Name = "apphost";
+}