feat: improve workflow for harper.js

[Asuka109]

This pull request includes several changes to improve compatibility and simplify the codebase. The most important changes involve updating the node version, switching from sed to perl for text replacement, and modifying the import statement in an example script.

• Setup .node-version file to install correct version of Node.js automatically.
• Use perl instead of sed to justfile and packages/harper.js/docs.sh since it take a better compatibility.
• packages/harper.js/examples/commonjs-simple/index.js: Changed the import statement for harper.js to use dynamic import so that it can load an esm module from a commonjs file.

The original sed statement will cause the error below:

> just setup                                                           
warning: /Users/asuka109/repositories/harper/harper-cli/Cargo.toml: unused manifest key: package.private
warning: /Users/asuka109/repositories/harper/harper-wasm/Cargo.toml: unused manifest key: package.private
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.39s
cd "/Users/asuka109/repositories/harper/harper-wasm" && wasm-pack build --target web
[INFO]: 🎯  Checking for the Wasm target...
[INFO]: 🌀  Compiling to Wasm...
warning: /Users/asuka109/repositories/harper/harper-wasm/Cargo.toml: unused manifest key: package.private
warning: /Users/asuka109/repositories/harper/harper-cli/Cargo.toml: unused manifest key: package.private
    Finished `release` profile [optimized] target(s) in 0.07s
[INFO]: ⬇️  Installing wasm-bindgen...
[INFO]: Optimizing wasm binaries with `wasm-opt`...
[INFO]: Optional fields missing from Cargo.toml: 'description', 'license'. These are not necessary, but recommended
[INFO]: ✨   Done in 16.55s
[INFO]: 📦   Your wasm pkg is ready to publish at /Users/asuka109/repositories/harper/harper-wasm/pkg.
sed: 1: "/Users/asuka109/reposit ...": command a expects \ followed by text
error: Recipe `build-harperjs` failed with exit code 1

[Asuka109]

Hi @elijah-potter! I encountered some issues while setup the project, so I created this PR to fix them. Could you please help to review it?

[elijah-potter]

This looks great! @Asuka109, thank you for fixing the problems for MacOS. I develop primarily on Linux, so I wasn't even aware there were issues 😄.

Just one thing before I can merge: would you mind modifying the GitHub Actions workflows to use the new .node-version file? It would be cool to have it centralized.

[Asuka109]

@elijah-potter Done~

[elijah-potter]

Looks great! Merging...