Consume PocketBase for posts and events, with English routes

Elternbeirat.Web.Tests/PocketBaseFixture.cs

@@ -49,6 +49,14 @@ public sealed class PocketBaseFixture : IAsyncLifetime
     /// <summary>Creates a <see cref="PocketBaseClient"/> pointed at this container.</summary>
     public PocketBaseClient CreateClient() => new(_http);
 
+    /// <summary>
+    /// The base URL the container's PocketBase is reachable at. Set once the
+    /// container is up; used to point the web app's client at this instance in the
+    /// route smoke tests.
+    /// </summary>
+    public Uri BaseUrl => _http.BaseAddress
+        ?? throw new InvalidOperationException("PocketBase is not started yet.");
+
     public async Task InitializeAsync()
     {
         // Clear any leftover from an earlier run that was aborted before DisposeAsync