Update i18n recipe and guide for better integration

[casungo]

Description

This PR addresses issue #9256 by updating the internationalization (i18n) recipe and guide to improve clarity, integrate modern Astro API features, and ensure they complement each other effectively.

Related issues & labels

• Closes Internationalization (i18n) guide and recipe should be merged #9256
• Suggested label: improve or update documentation

[netlify]

✅ Deploy Preview for astro-docs-2 ready!

Built without sensitive environment variables

Name	Link
🔨 Latest commit	66b2ec7
🔍 Latest deploy log	https://app.netlify.com/projects/astro-docs-2/deploys/68334170aa4a220008922e0b
😎 Deploy Preview	https://deploy-preview-11768--astro-docs-2.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[astrobot-houston]

Lunaria Status Overview

🌕 This pull request will trigger status changes.

Learn more

By default, every PR changing files present in the Lunaria configuration's files property will be considered and trigger status changes accordingly.

You can change this by adding one of the keywords present in the ignoreKeywords property in your Lunaria configuration file in the PR's title (ignoring all files) or by including a tracker directive in the merged commit's description.

Tracked Files

File	Note
en/guides/internationalization.mdx	Source changed, localizations will be marked as outdated.
en/recipes/i18n.mdx	Source changed, localizations will be marked as outdated.

Warnings reference

Icon	Description
🔄️	The source for this localization has been updated since the creation of this pull request, make sure all changes in the source have been applied.

[casungo]

Draft for now because I need to finish the last 2 recipes. But everything else is finished, reviews are welcome!