Issue 20: Documentation - API Reference

[adithya1012]

Description:
Create comprehensive Python API documentation with type hints and examples.

Acceptance Criteria:

• Create docs/API-PYTHON.md
• Document IndexedCPClient class and methods
• Document IndexedCPServer class and methods
• Document CryptoUtils class
• Document all keystore implementations
• Include type hints in documentation
• Add usage examples for each method
• Document configuration options
• Add error handling section