Keep workspace focus mode scoped and easy to exit (#2151)

* fix(workspace): keep focus mode scoped and easy to exit

Route focus mode through the active workspace so persisted state cannot hide chrome on settings or other screens. Add a visible exit control and keep desktop window chrome aligned and visually quiet.

* fix(app): clarify muted chrome semantics

packages/app/src/screens/settings-screen.tsx

@@ -1081,7 +1081,12 @@ function SettingsSidebar({
   );
 
   return (
-    <View style={outerContainerStyle} testID="settings-sidebar">
+    <View
+      accessibilityLabel={t("settings.title")}
+      role="navigation"
+      style={outerContainerStyle}
+      testID="settings-sidebar"
+    >
       {isDesktop ? (
         <View style={innerContainerStyle}>
           <View style={sidebarStyles.sidebarDragArea}>