Point the snackbar browser test at the region that moved

The live region is the toast host itself now, not a descendant of it, so the
selector that looked for `[aria-live]` inside the host found nothing. Plan step
11, actions.md ACT-02. (The Browser suite was not run from this worktree.)

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

tests/Browser/CommunicationTest.php

@@ -39,7 +39,8 @@ class RichTooltipMorphProbe extends Component
     }
 }
 
-const SNACKBAR = "document.querySelector('[x-data=\"materialSnackbar\"] [aria-live]')";
+// The live region is the host itself, in the page before any message is (actions.md ACT-02).
+const SNACKBAR = "document.querySelector('[x-data=\"materialSnackbar\"][aria-live]')";
 
 const TOAST = "document.querySelector('[data-toast]')";