- launchUrl called directly (drop canLaunchUrl gate that silently failed on
  Android without <queries> https scheme declaration)
- Store opens before dialog dismisses; pop guarded with context.mounted
- showForceUpdateWall/showMaintenanceWall/showUpdatePrompt use rootNavigator
  so walls survive splash-to-main navigation while async check is in flight
- clearStack param (default true) added to wall helpers

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>