Whisp [1] - Pure* PHP SSH server specifically designed for devs to build fun TUIs
Ended up having to write a decent chunk of C using FFI mind, no wonder people write SSH servers in Go/C, and why every AI tool told me it's really difficult and shouldn't be done :D
Bit of fun though, and I know more than I would ever want to know about the SSH protocol now!
And still not 100% sure if the sharding is the correct approach, but load-testing is promising so far