Improve error-page recovery navigation to prevent dead ends (#1103)

Author: Copilot

EssentialCSharp.Web.Tests/FunctionalTests.cs

@@ -51,5 +51,10 @@ public async Task WhenTheApplicationStarts_NonExistingPage_GivesCorrectStatusCod
         using HttpResponseMessage response = await client.GetAsync("/non-existing-page1234");
 
         await Assert.That(response.StatusCode).IsEqualTo(HttpStatusCode.NotFound);
+
+        string content = await response.Content.ReadAsStringAsync();
+        await Assert.That(content).Contains("Go Home");
+        await Assert.That(content).Contains("Go Back");
+        await Assert.That(content).Contains("Browse Chapters");
     }
-}
+}

EssentialCSharp.Web/Views/Home/Error.cshtml

@@ -16,6 +16,7 @@
     }
     <div class="d-flex gap-2">
         <a href="/home" class="btn btn-primary">Go Home</a>
+        <a href="/hello-world" class="btn btn-outline-primary">Browse Chapters</a>
         <button type="button" class="btn btn-secondary"
                 onclick="if(history.length > 1){ history.back(); } else { window.location='/home'; }">
             Go Back