add official hackathon tags from validator

fix: green user bubbles, light bot bubbles, no code blocks, readable chat

fix: textbox clickable, reject Tamil output, enforce Malayalam

feat: add browser TTS - auto-speaks responses in Malayalam

add social post link

update demo video link

fix: clean single-page chat UI, hide voice/image/reports in accordions

feat: match mobile app UI - green bubbles, chips, proper layout

fix: pin gradio 5.31.0 for huggingface_hub compatibility

Thuna - Offline AI Health Companion for Elderly - Build Small Hackathon