feature: implement LSP

[llllvvuu]

A bit of a long shot, but ruff implements it. As do ESLint and Biome f.k.a. Rome for JavaScript.

Benefit of a language server:

• perf: persistent process throughout an editing session
• code actions: treat single issues (ignore for this line, ignore for this file, fix this line)

LSP docs pygls docs

Potentially lower-hanging fruits:

• [x] Accept code input from stdin: https://github.com/Instagram/Fixit/pull/388
• [ ] Make it daemonizable: example. Probably not that worth it compared to just implementing LSP

Related: https://github.com/Instagram/Fixit/issues/122 - many VSCode extensions are built using LSP. Just wanted to flag the protocol since there is a failure mode of building a VSCode extension without the protocol and thus not supporting other editors.

Workaround: let third-parties build daemons/LSPs off of the Fixit API