refactor(examples): refactor example instructions

[vados-cosmonic]

This PR refactors the example and makes it a little easier to follow, separating the Rust and JS components and updating the test script.

[leoyvens]

Should the API section of the README also be updated? It doesn't seem to reflect the current API.

[vados-cosmonic]

Hey @leoyvens I think you're right -- would welcome a PR (+/- issue!) to update the main README! I'm not sure that page has seen a change in a while.

[guybedford]

Just let me know when this one is ready for review and it would be great to take a look further.

[vados-cosmonic]

Sorry, the CI to run the updated test.sh script still wasn't right -- GH actions changes + typos that snuck in. The refactor itself doesn't change the projects themselves dramatically, but the script to orchestrate the tests did change a bit.

Should be good to go -- CI is 🟢 except for the AOT performance check that has been failing for a while now on main (which is unrelated):

  1) Builtins
       performance:
     Error: took more than half a millisecond - 3.469573974609375 ms
      at test (file:///home/runner/work/ComponentizeJS/ComponentizeJS/test/builtins/performance.js:26:11)
      at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
      at async Context.<anonymous> (file:///home/runner/work/ComponentizeJS/ComponentizeJS/test/test.js:76:9)

[guybedford]

This is great, thanks for the PR.