Could you add Singbox support to AdGuard? Would it be possible to implement proxy functionality within AdGuard

### Issue Details

Apple's paid proxy apps already support MITM interception, but Android proxy apps can't do that. Adguard and proxy apps don't work together either (the speed will be really slow when used together)
I really hope AdGuard would develop a proxy feature, and that AdGuard VPN also supported subscription rules so I could import AdGuard VPN's nodes into my proxy software
I really hope AdGuard and AdGuard VPN can keep getting better. I really like AdGuard VPN, but it's not as easy to use as a real proxy app, and AdGuard doesn't support the features of a real proxy app at all

### Proposed solution

Adding a Singbox core (you could try modifying Singbox yourself), I don't think that would be hard to do - just add a Singbox core on the backend and keep using AdGuard for filtering on the frontend. If AdGuard doesn't move towards developing proxy software, it'll have a hard time moving forward. Looking at other proxies on GitHub, a lot of people are using them. If you don't make progress and develop, AdGuard might have a really tough time surviving

### Alternative solution

_No response_