Add more comments around workerd usage

[frandiox]

Adding some extra comments around workerd extracted from #2574
This area is somewhat complex so I thought this could help.

[github-actions]

We detected some changes in packages/*/package.json or packages/*/src, and there are no updates in the .changeset.
If the changes are user-facing and should cause a version bump, run npm run changeset add to track your changes and include them in the next release CHANGELOG.
If you are making simple updates to examples or documentation, you do not need to add a changeset.

[shopify]

Oxygen deployed a preview of your fd-mini-oxygen-comments branch. Details:

Storefront	Status	Preview link	Deployment details	Last update (UTC)
classic-remix	✅ Successful (Logs)	Preview deployment	Inspect deployment	September 30, 2024 9:47 AM
third-party-queries-caching	✅ Successful (Logs)	Preview deployment	Inspect deployment	September 30, 2024 9:47 AM
Skeleton (skeleton.hydrogen.shop)	✅ Successful (Logs)	Preview deployment	Inspect deployment	September 30, 2024 9:47 AM
sitemap	✅ Successful (Logs)	Preview deployment	Inspect deployment	September 30, 2024 9:47 AM
metaobjects	✅ Successful (Logs)	Preview deployment	Inspect deployment	September 30, 2024 9:47 AM
custom-cart-method	✅ Successful (Logs)	Preview deployment	Inspect deployment	September 30, 2024 9:47 AM

Learn more about Hydrogen's GitHub integration.