Add comprehensive backend test suite and helper access

GameList.Tests/ResultsTests.cs

@@ -32,4 +32,15 @@ public class ResultsTests
         Assert.Equal("ResultGame", first.GetProperty("name").GetString());
         Assert.Equal(8, (int)first.GetProperty("average").GetDouble());
     }
+
+    [Fact]
+    public async Task Results_locked_returns_error()
+    {
+        using var factory = new TestWebApplicationFactory();
+        var client = factory.CreateClientWithCookies();
+        await client.RegisterAsync("user");
+        await client.PostAsJsonAsync("/api/me/phase/next", new { });
+        var resp = await client.GetAsync("/api/results");
+        Assert.Equal(System.Net.HttpStatusCode.BadRequest, resp.StatusCode);
+    }
 }