fix(ui): EDIT label is white in both states

The armed state was fixed to on-accent last build, but the resting state kept on-surface-variant
(#94a3b8) — so with EDIT off, which is its normal state, the label was grey on the dark bar. The
label is white always now; only the fill changes (neutral → blue). The redundant foreground setter
is gone, and UiShellTests asserts the resting colour rather than the trigger.

ytLive.Tests/UiShellTests.cs

@@ -30,7 +30,9 @@ public class UiShellTests
         // 2. EDIT: resting face differs from the armed face, and the label follows it.
         Assert.Contains("x:Name=\"EditBody\" Background=\"{StaticResource Brush.SurfaceContainerHigh}\"", topBar);
         Assert.Contains("<Setter TargetName=\"EditBody\" Property=\"Background\" Value=\"{StaticResource Brush.Tertiary}\"/>", topBar);
-        Assert.Contains("<Setter Property=\"Foreground\" Value=\"{StaticResource Brush.OnAccent}\"/>", topBar);
+        // The label is white in BOTH states — only the fill changes. A muted resting colour is
+        // what made it illegible on the dark bar (creator, 2026-10-30).
+        Assert.Contains("FontSize=\"12\" Foreground=\"{StaticResource Brush.OnAccent}\"", topBar);
 
         // 3. Active scene = orange; live stays red.
         Assert.Contains("IsStaged}\" Value=\"True\">\n                                        <Setter Property=\"BorderBrush\" Value=\"{StaticResource Brush.Attention}\"/>", strip);