fix: import nuxt composables from #imports

[danielroe]

🔗 Linked issue

❓ 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

This is a DX improvement when developing - we can avoid loading the entire barrel file at #app by using the new granular imports merged in nuxt/nuxt#23951.

📝 Checklist

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