feat: Local HTTP Server

[grencez]

A local HTTP server would be a nice way to dockerize and prototype an interface. My rough design would be:

• A simple Python-based webserver to avoid new dependencies for now. Put it in a new directory under src/.
• Webserver launches the chat CLI and communicates with it via coprocess commands (see assistant_coprocess example).
• Webserver serves the client HTML + JS + CSS and also exposes a JSON or websocket endpoint for the interactive chat.

[grencez]

Since I plan to use WebRTC for the remote server, it would make sense to pull in the https://github.com/paullouisageneau/libdatachannel/ library now and use its websocket functionality for the local server. It also pulls in a JSON library, which could be convenient.

Not sure what to do about the webpage serving though. I can roll a simple http server, but it would have to hand off to the websocket (on the same port) I guess? Unclear.

[grencez]

In the long term, it's probably best for the local server behave like the remote server and use WebRTC.
So in the short term, I once again prefer the original idea of a dumb HTTP-only interface that responds to JavaScript polling.

Code layout can be:

• Fildesh gets a new struct that listens for TCP connections. Can be called FildeshTcpService.
  • Preallocates some number of data structures used for request & response.
  • Accept function that returns a FildeshX and FildeshO for the HTTP request and response.
  • The FildeshX and FildeshO are specialized.
    • "close" marks the struct as available for newly accepted connections to reuse.
    • "close" doesn't close the whole socket until both input & output are closed. It does call shutdown though.
    • "read" and "write" must be implemented with send() and recv() due to Windows.
• Rendezllama can implement the format of http request and response. It won't be complicated.

[grencez]

Alternatively... It would be even easier to use a simple python or nodejs process that spawns the chat executable and serves some html & javascript content. Might as well start there...

The coprocess funcitonality was added in #22.

[grencez]

I only know basic web stuff, so anyone is free to pick this up. See updated description.