Update model from qwen3:4b to qwen3:1.7b

Add API key authentication and tech specifications document

feat: Change model to qwen3:4b

feat: Change model to qwen3:8b

fix: Correct model name to qwen3:1.7b

feat: Change model to qwen:1.5b

feat: Use qwen3:4b model

feat: Add chat interface and versioned API

fix: Install curl in Dockerfile

fix: Use ENTRYPOINT to fix runtime error

fix: Add --break-system-packages to pip install

feat: Add FastAPI gateway for API key authentication