test(ui): follow the relocated settings gear

HANDOFF.md

@@ -13,20 +13,22 @@
   `82609a5`.
 - `NotificationServiceTests` runs tint assertions with real theme resources and uses the current
   `Brush.ErrorContainer` token; committed as `caf91e6`.
-- `ScoreboardSimulationTests` now checks the shared `Helpers/DevBuild.cs` compile-time gate; focused
+- `ScoreboardSimulationTests` now checks the shared `Helpers/DevBuild.cs` compile-time gate;
-  test passes. This task is ready to commit.
+  committed as `0e1f948`.
-- Clean app build is 0 warnings. Full suite: 4 failed / 518 passed of 522; remaining failures are
+- `UiShellTests` now checks the orange Settings gear on the preview rail and the EDIT/session
+  ordering in the top bar; focused test passes. This task is ready to commit.
+- Clean app build is 0 warnings. Full suite: 3 failed / 519 passed of 522; remaining failures are
   being handled one task and one local commit at a time.
 
 ## Next action
 
-Commit the scoreboard-simulation guard update, then take the next remaining failure. Do not push
+Commit the UiShell assertion update, then take the next remaining failure. Do not push absent a
-absent a milestone/checkpoint request.
+milestone/checkpoint request.
 
 ## Landmines
 
 - Build/test with Windows `dotnet.exe`; the full suite can hang in WASAPI teardown.
-- `verify.sh` cannot pass until the remaining 4 suite failures are resolved; scope checks are run
+- `verify.sh` cannot pass until the remaining 3 suite failures are resolved; scope checks are run
   separately when that gate exits early.
 - Any integration test constructing `MainWindow` must set `LayoutPathOverride` to a temporary DB
   and clear it in `finally`.

ytLive.Tests/UiShellTests.cs

@@ -75,17 +75,25 @@ public class UiShellTests
     }
 
     [Fact]
-    public void Edit_sits_beside_the_orange_gear()
+    public void Settings_gear_is_orange_on_the_preview_rail_and_EDIT_precedes_the_session_cluster()
     {
         var topBar = SourceAssert.Text("Controls", "TopBar.xaml");
+        var preview = SourceAssert.Text("Controls", "PreviewPane.xaml");
 
-        // The gear is a LlamaCasty control, so it wears the app's orange (not a muted icon grey).
+        // The settings gear moved from the top bar to the first orange preview-rail tab.
-        Assert.Contains("Fill=\"{StaticResource Brush.Attention}\" Width=\"18\" Height=\"18\"", topBar);
+        var settingsTooltip = preview.IndexOf("ToolTip=\"Settings\"", System.StringComparison.Ordinal);
+        Assert.True(settingsTooltip >= 0, "the Settings gear tab is missing from the preview rail");
+        var gearStart = preview.LastIndexOf("<Border ", settingsTooltip, System.StringComparison.Ordinal);
+        var gearEnd = preview.IndexOf("</Border>", settingsTooltip, System.StringComparison.Ordinal);
+        Assert.True(gearStart >= 0 && gearEnd > settingsTooltip, "the Settings tab has no bordered gear surface");
+        var gear = preview[gearStart..gearEnd];
+        Assert.Contains("Background=\"{StaticResource Brush.Attention}\"", gear);
+        Assert.Contains("MouseLeftButtonUp=\"SettingsTab_Click\"", gear);
+        Assert.DoesNotContain("ToolTip=\"Settings\"", topBar);
 
-        // EDIT lives in the LEFT cluster, immediately after the gear — not in the centre session
+        // EDIT stays in the left brand cluster, before the centre session cluster.
-        // cluster (creator ruling 2026-10-30).
         var edit = topBar.IndexOf("EditingActive", System.StringComparison.Ordinal);
-        var centre = topBar.IndexOf("Grid.Column=\"1\"", System.StringComparison.Ordinal);
+        var centre = topBar.IndexOf("<StackPanel Grid.Column=\"1\"", System.StringComparison.Ordinal);
         Assert.True(edit > 0 && centre > edit,
             "the EDIT toggle must appear before the centre (session) cluster");
     }