Update README.md

Update readme

Add links to blog, video, social post, and HF spaces to README

Update README link to build-small-hackathon org

Clean repo, update README, improve .gitignore for hackathon

Fix: use sdk docker for Python 3.11 compatibility, relax gradio version

UX overhaul + Gradio migration + remove llama.cpp

Space: prebuilt llama-cpp-python wheel, minimal Dockerfile

Initial commit