Server Process Management & IPC

[hbjydev]

HARM will need some kind of background process manager to manage multiple servers cleanly, to ensure we can manipulate processes without creating zombies while still being able to manage them programatically (via the API).

Requirements:

• Start/stop/restart a process programatically and asynchronously (these actions will exist in an API endpoint, and there will be multiple processes that can be spawned) #11
• Tail the logs for the processes programatically and asynchronously (like you would with CI logs in a browser) #9
• Do something when the process fails (i.e. updating DB or in-memory state to say 'hey, this process died') #10

Examples:

• Start a server: curl -XPOST localhost:8080/servers/<id>/start
• Stop a server: curl -XPOST localhost:8080/servers/<id>/stop
• Check a server's status: curl localhost:8080/servers/<id>/status
• Restart a server: curl -XPOST localhost:8080/servers/<id>/restart
• Get logs for a server (for all time, newest first): curl localhost:8080/servers/<id>/logs?since=0&sort=desc

These'll get wrapped in a CLI and SDK that can be used to build other stuff (like a Tauri desktop app, some kind of web UI, or a Discord bot). Each of these needs to start a binary from a specific directory on the host (the Reforger Server install directory which we already grab in the existing start endpoint), while not caring where the API itself is running.

This'll be... an annoying problem to solve lol