Add Clarvia AEO badge — measure FastChat's agent ecosystem compatibility

[digitamaz]

Hi FastChat team! 👋

Clarvia scores 27,900+ AI tools using AEO (Agent Engine Optimization) — measuring how well tools support autonomous agent workflows.

FastChat is a leading LLM serving platform used extensively in agent deployments. An AEO badge shows developers that FastChat meets the compatibility standards for agent workflows:

[![AEO Score](https://clarvia.art/api/badge/lm-sys/fastchat)](https://clarvia.art)

Thanks for the outstanding work on open LLM serving! Would you consider adding this badge? 🚀