Major Update with FastAPI and New Calculations

feat: Rework server to FastAPI and add new astrology calculations

This commit introduces a major refactoring of the server backend:

• The backend has been rewritten from Flask to FastAPI for improved performance and asynchronous support.
• New API endpoints have been added for calculating daily, monthly, and yearly horoscopes.
• A new endpoint for synastry (compatibility) chart calculations has been implemented.
• The version of the API has been updated to v0.2.0 to reflect these significant changes.