What changed

When the "Extra notification" setting is enabled, the permanent "No device" notification now shows a hint telling users they can disable it in system settings. This helps users understand which notification channel to turn off to hide the persistent status notification while keeping the separate "Connected device" notification.

Technical Context

• The hint only appears on the primary foreground notification (ID=1) when no device is detected and the extra notification setting is active
• When a device is connected, the notification switches to the custom device view — the hint is not shown
• Added a showHint parameter to getBuilder()/getNotification() with false default so existing callers (getStartupNotification, getNotificationConnected) are unaffected
• Uses BigTextStyle.bigText() to display the hint as expandable body text under the "No device" title