Add AEO quality badge to README (score: 32/100)

[digitamaz]

Hi! I'm behind Clarvia — an open quality scoring platform for AI tools.

Diffusers has an AEO (Agent Experience Optimization) score of 32/100 on Clarvia.

Embed a live badge in your README:

[![AEO Score](https://clarvia.art/api/badge/diffusers)](https://clarvia.art/tool/diffusers)

Full profile: https://clarvia.art/tool/diffusers — score breakdown with improvement suggestions.