Add ESLint

[vgeorge]

At the moment, we have Prettier formatting checks and TypeScript checks, but not ESLint checks. Adding ESLint would help us improve JavaScript code quality and maintain consistency across the codebase.

cc @kylebarron @batpad

[kylebarron]

I'm happy to do this. Do you have any opinions about newer alternatives like oxlint?

[vgeorge]

This is the first time I'm hearing about oxlint, it looks very interesting. My main concern is whether it has good integration with VSCode. If the development experience is similar to using ESLint, I think we can give it a try.

[vgeorge]

@kylebarron I looked into oxlint, it seems very bleeding edge. I created an oxlintrc.json file with the no-console and no-unused-vars rules enabled, but the oxc VS Code extension isn't able to pick it up.

[kylebarron]

That's fine; a PR to add eslint would be great