design: app settings + dialogs to tokens (surface 5 of the sweep)

OverlayHost (the App Settings surface) and every dialog — Go Live, Socials, Mic picker, Camera
picker, Hotkey config, Reuse Image, Rename Recording, Keep Broadcast — now resolve from tokens.
That closes the last place the creator sees a dialog: the settings overlay was still wearing the
old palette while the main window had moved on.

Every #e94560 in these files was an ERROR or validation affordance (hotkey conflicts, socials
validation, the remove tooltip, the go-live error line) — six sites all borrowing the retired
brand red to mean "something is wrong". They are `error` now, which is what the standard says
red-adjacent means; live/record keeps `primary`.

Guard list extended to all nine files.

ytLive.Tests/DesignTokensTests.cs

@@ -76,7 +76,11 @@ public class DesignTokensTests
         // are allowed (gloss highlights, knockout masks) — everything else must be a token.
         string[] converted = { "Themes/Controls.xaml", "MainWindow.xaml", "Controls/TopBar.xaml", "Controls/SceneThumbnailStrip.xaml",
                                  "Controls/LeftPanel.xaml",
-                                 "Controls/PreviewPane.xaml" };
+                                 "Controls/PreviewPane.xaml",
+                                 "Controls/OverlayHost.xaml", "SocialsDialog.xaml", "GoLiveWindow.xaml",
+                                 "HotkeyConfigDialog.xaml", "MicPickerDialog.xaml", "CameraPickerDialog.xaml",
+                                 "ReuseImageDialog.xaml", "RenameRecordingDialog.xaml",
+                                 "KeepBroadcastDialog.xaml" };
 
         foreach (var file in converted)
         {