fix: use correct module type for node/ (cjs)

[IvanVishnevskiy]

Currently, we build esm, bundler and node (CJS) targets. However, the main package.json inherits { "type": "module" } set by the bundler output during copying in

parquet-wasm/scripts/build.sh

Line 53 in 2dbda63

jq -s '.[0] * .[1]' templates/package.json tmp_build/bundler/package.json > pkg/package.json

This means that our CJS export node/ has type module so any CJS Node.JS application would fail to import it.

By simply adding {"type": "commonjs"} to node/package.json, we ensure that node can correctly resolve the right type for that target.

This fixes #798

[IvanVishnevskiy]

Built the project locally and used npm link to verify - getting correct behavior now with Node.js 24.
With this code:

import { readParquet } from 'parquet-wasm';
console.log(readParquet);

Previously:

file:///home/<redacted>/parquet-wasm/pkg/node/parquet_wasm.js:3
imports['__wbindgen_placeholder__'] = module.exports;
                                      ^

ReferenceError: module is not defined in ES module scope
This file is being treated as an ES module because it has a '.js' file extension and '/home/<redacted>/parquet-wasm/pkg/package.json' contains "type": "module". To treat it as a CommonJS script, rename it to use the '.cjs' file extension.
    at file:///home/<redacted>/parquet-wasm/pkg/node/parquet_wasm.js:3:39

After the fix:

[Function (anonymous)]

[github-actions]

Asset	Size	Compressed Size
report_pkg/async_full/parquet_wasm_bg.wasm	6.4MB	1.3MB
report_pkg/slim/parquet_wasm_bg.wasm	4.6MB	658KB
report_pkg/sync/parquet_wasm_bg.wasm	5.9MB	1.2MB