Add FRED API key validation at app startup and improve environment variable loading

Fix frequency error and analytics availability issues - Fixed Invalid frequency: ME error by changing freq='ME' to freq='M' - Updated analytics availability check to verify modules directly - Improved error handling for real FRED data processing - Enhanced configuration page to show accurate analytics status

Remove all demo data and update project to use only real FRED API data

Optimize Streamlit app performance with lazy imports and loading indicators

Fix Streamlit Cloud deployment issues and deprecated pandas warnings

Prepare for Streamlit Cloud deployment - Add deployment files, fix clustering chart error, update requirements

feat: Integrate advanced analytics and enterprise UI

feat: Complete project cleanup and professional structure