Add a mobile nav and pin the header while scrolling

Elternbeirat.Web.Tests/PocketBaseClientTests.cs

@@ -85,7 +85,9 @@ public sealed class PocketBaseClientTests(PocketBaseFixture pocketBase)
 
         var home = pages.Single(p => p.Slug == "home");
         home.Embed.ShouldBe(["posts", "events"], ignoreOrder: true);
-        home.Location.ShouldBe("header");
+        // Home has no menu slot: the brand is the home link, so a "Start" nav
+        // entry would be redundant. NavBuilder filters it out via this empty value.
+        home.Location.ShouldBe("");
     }
 
     [Fact]