fix: set default model to Gemma

[netlify[bot]]

✅ Deploy Preview for chatty-ai ready!

Name	Link
🔨 Latest commit	a247c5b95675f92a35718382e985b0c7ff3c00fe
🔍 Latest deploy log	https://app.netlify.com/sites/chatty-ai/deploys/666f35056b440c0008865811
😎 Deploy Preview	https://deploy-preview-61--chatty-ai.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 site configuration.