[Feature Request] Restore/Add App Shortcuts for connection toggling (Android / Samsung Modes & Routines)

Is your feature request related to a problem? Please describe.

In current versions of sing-box for Android, system automation tools (such as Samsung's Modes and Routines, Tasker, etc.) can only trigger the standard "Open application" action.

Previously, an App Shortcut / Quick Action (sing-box Toggle) was available, allowing users to toggle the proxy/VPN service state directly in the background without opening the main UI.

Describe the solution you'd like

Please consider restoring or adding Android App Shortcuts (android:shortcuts / ShortcutManager) or Intent actions for controlling the VPN state:

• Toggle service (Start/Stop)
• Start service
• Stop service

This would allow native integration with Android automation tools (e.g., automatically toggling sing-box when connecting to specific Wi-Fi networks or launching specified apps via Samsung Modes and Routines).

Describe alternatives you've considered

Using third-party automation tools like MacroDroid or UI click macros via Routines+, which are less reliable and require extra setup compared to native App Shortcuts.

Additional context

Samsung One UI "Modes and Routines" relies on registered Android App Shortcuts to expose app actions to users. Having static shortcuts would restore seamless background automation for Samsung Galaxy and other Android devices.

Start by locating the Android app's existing shortcut declarations or ShortcutManager integration, then trace the VPN service actions exposed to the app. Check how Samsung Modes and Routines discovers registered shortcuts; done means static actions exist for toggling, starting, and stopping the service without opening the main UI.