test(ui): read notification colors from app theme

ytLive.Tests/NotificationServiceTests.cs

@@ -11,8 +11,13 @@ namespace ytLive.Tests;
 /// Errors must never auto-expire (sticky until dismissed); the rest get short
 /// lifetimes; everything routes to the in-window ToastArea.
 /// </summary>
+[Collection("RealApp")]
 public class NotificationServiceTests
 {
+    private readonly RealAppHost _app;
+
+    public NotificationServiceTests(RealAppHost app) => _app = app;
+
     [Theory]
     [InlineData(AppNotificationSeverity.Info, 4)]
     [InlineData(AppNotificationSeverity.Success, 4)]
@@ -39,11 +44,14 @@ public class NotificationServiceTests
     [InlineData(AppNotificationSeverity.Info, "#3a3b52")]
     [InlineData(AppNotificationSeverity.Success, "#1d5c38")]
     [InlineData(AppNotificationSeverity.Warning, "#b8860b")]
-    [InlineData(AppNotificationSeverity.Error, "#8f1f1f")]
+    [InlineData(AppNotificationSeverity.Error, "#93000a")]
     public void Severities_Map_To_Dark_Card_Tints(AppNotificationSeverity severity, string expectedHex)
     {
-        var request = NotificationService.BuildRequest("Title", "Body", severity);
+        _app.Run(() =>
+        {
+            var request = NotificationService.BuildRequest("Title", "Body", severity);
 
-        Assert.Equal(expectedHex.ToLowerInvariant()[^6..], request.BackgroundColor!.Value.ToHex().ToLowerInvariant()[^6..]);
+            Assert.Equal(expectedHex.ToLowerInvariant()[^6..], request.BackgroundColor!.Value.ToHex().ToLowerInvariant()[^6..]);
+        });
     }
 }