[FEATURE] - Allow copying and pasting package IDs for Split Tunneling via clipboard

[wtxsu]

Please add an option to copy and paste the list of apps (package IDs) for Split Tunneling / Per-App VPN via the clipboard, similar to how it is implemented in many proxy clients (e.g., v2rayNG, Sing-box, NekoBox).

Use case / Why it's needed:

• Manually checking/unchecking dozens of apps in the UI takes a lot of time.
• It makes it much easier to share, back up, or migrate Split Tunneling rules between devices.

Suggested implementation:

• "Copy to Clipboard": Exports the currently selected apps as a plain-text list of package IDs (e.g., com.example.app, separated by newlines or commas).
• "Paste from Clipboard" / "Import": Reads a list of package IDs from the clipboard and automatically selects the corresponding installed apps.