Add support for transfer packets

[cadenkriese]

I added a accept_transfers config boolean, which is false by default. When accept_transfers is set to true, PicoLimbo will accept incoming connections with the transfer intention.

I also added a /transfer <hostname> [<port>] command that transfers the player who executes it to the specified hostname and port.

Demo

PicoLimbo_Transfer_Demo.mp4

AI Usage Disclosure

All code was written by me. I used ChatGPT 5.2 and Google Gemini 2.5 for help with Rust syntax as I've never used the language before and for some help explaining the codebase.

[Quozul]

This looks good to me. While testing it, I noticed two improvements:

• Update the documentation in the docs directory to mention the new accept_transfers setting
• Packet IDs are missing for the transfer packet for versions prior to 1.21, this has to be manually added to each packets.json files for the concerned versions (1.20.5 or greater)

[cadenkriese]

Thanks for those pointers. Two questions I have:

Should the transfer command be disabled by default since it is usually a command reserved for operators?

Also, I noticed the /transfer (without any arguments) brigadier node is marked as executable, which causes the client to render the hostname as an optional paramater instead of required, as denoted by the brackets []:

I was thinking I could add a requiredArgumentCount int to the Command struct in commands_packet.rs and then only mark nodes after that count as executable. Would that work or would you prefer something else?

[Quozul]

Should the transfer command be disabled by default since it is usually a command reserved for operators?

That's a good question; I don't know 😅
The thing is, to disable a command, you have to set an empty string in the config file, which looks weird to me in a default config file. The best would be to update the commands config to something like this 🤔

[commands.transfer]
enabled = false
alias = "transfer"

This can be done in another pull request and leave the command available to everyone for now. It could also allow to whitelist some players in the future, for example, to run a reload or stop command.

Also, I noticed the /transfer (without any arguments) brigadier node is marked as executable, which causes the client to render the hostname as an optional paramater instead of required, as denoted by the brackets
I was thinking I could add a requiredArgumentCount int to the Command struct in commands_packet.rs and then only mark nodes after that count as executable. Would that work or would you prefer something else?

A required argument count int could work. I probably would've added a is executable bool to the arguments. Whichever you prefer!

[cadenkriese]

Thanks again for your help. I'm happy with this now as long as you are.