Add dedicated Nuxt section

[miguelfernandezdev]

Organize the existing Nuxt questions into a dedicated section and expand coverage.

Currently there are 20+ Nuxt questions mixed into the general Q&A. A dedicated section would:

• Group existing Nuxt content under its own navigation
• Add deeper guides on Nitro, server routes, and hybrid rendering
• Cover Nuxt modules ecosystem (content, image, auth, etc.)
• Add deployment guides (Vercel, Netlify, Node, edge)

This is a structural change — discuss approach in this issue before opening a PR.