Improve agent chat tone and HF fallback behavior

Update HF router models and inference flow

Replace unavailable models with HF Inference API-verified models (Mistral, Llama 2, Zephyr, etc.)

Add contextual chat message generation when HF models don't return messages

Add comprehensive logging for HF API token and inference failures

Remove Groq models; switch registry and clients to HF-only curated list

Add Groq->HF fallback mapping and accept HUGGINGFACE_API_TOKEN

Add 15+ free HF models, expand model selection, add debug logging

Keep both Groq + HF models, remove rate-limited Groq models, unify model selection UI without backend labels

Use model-authored dynamic chat with recent radio context

inital build