Chat sync V1

[Xernium]

This is an attempt at allowing servers behind Velocity on 1.19.1 to use secure chat.
Related to https://github.com/PaperMC/Paper/pull/8219

[Aurelien30000]

Hey! If you need me to test something about your fight against last seen chat messages, I have a setup of a velocity proxy and two backend paper servers locally (remotely if needed). Atm, same error as usual.

[kyngs]

Would this also fix #770 ?

[davidmayr]

Whats the status of this?

[D3it7i]

I have a suggestion, especially this pr seems to be difficult to complete, an optional option, when turned on, only verify the player chat security in the proxy server, so that the chat report on the client side works normally, and the backend server says the chat is not Safe, but the backend is all under a secure network, isn't it?

[electronicboy]

Secure network is 100% irrelevant, you can't handle this stuff on just the proxy because the entire state of the chain needs to be maintained on the backend server. There is ongoing efforts to work on this stuff however it is a moving target as mojangs system is still also irrelevant, in part which should aid this issue

[D3it7i]

the entire state of the chain needs to be maintained on the backend server.

Why need back-end server maintenance, when you just want the back-end server to record an unsafe chat message. Isn't the server just responsible for verifying signatures and broadcasting chat signatures?

[Xernium]

I am currently not active as developer but let me say: it’s not that simple. This PR is heavily outdated due to me rebasing a ton of stuff before going into hiatus. See https://github.com/xernium/Velocity/tree/work/wip/s02 if you want to see where I left of