Now that `apps/oxlint` and `napi/parser` are both ESM packages (#13723 and #14042), we can use `.js` file extensions for all ESM files, rather than the mix of `.js` and `.mjs` file we had previously.
It's less confusing having to remember what's `.js` and what's `.mjs`, and avoids ugly workarounds like #14038 (`.d.mts`??).
Pure refactor. Root of `napi/parser` was getting really crowded with tons of files, and I'm about to add a load more for the ESTree walker.
Move JS source files into a `src-js` directory, like in `apps/oxlint`, so that the root of the package is just config files and scripts.
Same as #13184.
#13173 enabled Oxlint for all the repo, but we currently skip `napi` directory.
Fix all errors that Oxlint flags in `napi/parser`.
We currently can't turn on Oxlint for the directory, because `oxlint-disable` comments don't work for type-aware rules, but we should be able to once that's fixed.
Boshen