feat: Add audio analysis service using FastAPI

Commit notes

This commit introduces a new FastAPI-based microservice for audio analysis. It includes:

- Dockerfile and entrypoint script for containerization. - Environment configuration (`.env.example`). - Core analysis logic in `app.py`, `dsp.py`, and `embed.py`. - Database interaction (`db.py`) for storing features and metadata. - S3-compatible storage integration (`r2.py`). - Projection logic (`project.py`) for generating 2D embeddings. - Pydantic models for API requests and responses. - Basic unit tests.

Co-authored-by: armin.naimi <[email redacted]>