Tor-powered apps should be routed through Tor VPN's proxy when available

Instead of letting tor powered applications bypass tor and expecting them to handle tor themselves, I feel it would be better for them to reuse the tor from the vpn, through an exposed socks5(or similar) port, similarly to how oniux exposes a proxy on [::1]:9050 for applications to use (though there, I understand that it's moreso in order to tell applications it's okay to try and use .onion addresses, afaik)

I feel this is a better long term design for reasons of

  1. Only one set of guards. If I have tor vpn, and tor browser android, and onionshare installed and use them, guard fingerprinting gets easier since I effectively have 3 times the guards. (Since they'd be using different guards, a local attacker can also see how much I'm using each application, and when)

  2. Only one copy of Tor on the system in use (so it's less critical to update applications that use tor)

  3. Applications can choose to isolate further for application specific things (multi-account?)

    This is more for "applications that aren't always using tor, but are at least tor aware". They could be told "hey, you're going over Tor, there's a socks proxy [here] if you want to do stream isolation", so 2 accounts on the same site can be isolated if the application wants to.

  4. Applications can't accidentally leak. Even though there's a socks proxy, if they don't use it, the data still goes over tor(again, what oniux does), so this wouldn't be a downside in terms of security.

This would require some way for applications to recognise if they're going over tor vpn (I'm not suggesting tor vpn be made a hard dependency for tor browser android, TBA would still need to ship a tor client, but use tor vpn's proxy if it's installed)

One wrinkle would be features that require the application to use the controlport (circuit viewing?). Just letting applications see the circuit IPs would be dangerous in general, so either it'd need to be permissioned on torvpn's side, or applications ask torvpn to show the circuit for them as a popup of some form.