[Backend] Initialize FastAPI Project Structure

[aceblack10]

Description:
We need to set up the foundational directory structure for the FastAPI backend. This should follow a scalable pattern to accommodate future modules like the Readiness Engine and Ollama integration.

Tasks:

• Create /backend directory.
• Initialize a main.py with a basic health check endpoint (/health).
• Add a requirements.txt or pyproject.toml with fastapi and uvicorn.
• Include a basic README.md within the backend folder explaining how to run it locally.