feat(nuxt): server-only components

[danielroe]

🔗 Linked issue

• Pending: feat(nuxt): experimental server component islands  #5689 (Implements: https://github.com/nuxt/framework/discussions/666)
• Resolves Server only components nuxt#11856

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

Summary

This PR adds support for:

1. rendering individual components through a special GET request to /__nuxt_render (implementing RFC https://github.com/nuxt/framework/discussions/666)
2. registering and rendering server components with .server.vue suffix (implementing Server only components nuxt#11856), including injecting scripts + styles from this render back into client-side DOM. As part of this, we only build CSS from server-components into client build (which is required), meaning the code from server-components won't be present in your client bundle.

Next steps

• The key next step is to review to see if we want to make any changes to RFC or spec.
• Update documentation with details about server (+ client) components

Future improvement ideas

1. 'Batching' server component updates
2. Detect 'dependencies' of server components so entire state doesn't need to be pushed
3. Detect 'effects' of server components so entire state doesn't need to be returned from renderer
4. Move server-only component CSS out of manifest (but this can also be handled as part of solution to Nuxt 3 prefetch all assets from every pages and every layouts. nuxt#13778)

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

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[atinux]

Happy to review when not in draft anymore (cannot wait BTW!)

[danielroe]

👍 This is waiting for merge of #5689.

[cumhuronat]

Will this be included in rc14?

[danielroe]

This is waiting on #5689.

[cumhuronat]

This is waiting on #5689.

not anymore :)

[joezimjs]

So this is coming in 3.1? When should we expect to be able to start trying this out?

[danielroe]

3.1 will be coming imminently. 👀

But you can always try things out in the edge channel, and in fact we really appreciate people testing the edge to catch regressions early.