Support GROQ_API_KEY env var name (HuggingFace requires underscores, no hyphens)

Add Dockerfile and HuggingFace Spaces README for free hosting

Fix port binding: use directly so Render/Railway can detect open port

Remove chromadb (unused, pulls in 500MB+ CUDA packages causing build timeout)

Fix Railway build: use requirements.txt natively, remove nixpacks.toml

Fix Railway build: use nixpacks.toml for reliable Python+uv install

Fix Railway build: skip npm (frontend/dist already committed, just install Python deps)

Add README and main.py

Fix Railway deployment: add built frontend/dist, fix railway.toml