test: classify prerequisite lanes and own Avalonia sessions

tests/AcDream.App.Tests/UI/Layout/InventoryFrameImportProbe.cs

@@ -18,6 +18,7 @@ namespace AcDream.App.Tests.UI.Layout;
 /// backdrop (ZLevel 100 → ≈ −1,000,000), and the backdrop washed out the panels' captions,
 /// burden meter, and item cells. Skips when the live dat directory is absent (CI).
 /// </summary>
+[Trait("Lane", "InstalledDat")]
 public class InventoryFrameImportProbe
 {
     private const uint Frame          = 0x21000023u;