Project cleanup: fix data flow bug, remove dead code, update docs

Fix remaining medium/low severity bugs from audit

Fix 11 bugs found in audit (critical + high severity)

Add comprehensive test framework with 159 tests and report generation

Complete all roadmap tasks: portfolio, sentiment, WebSocket, and more

Add candlestick chart, model persistence, SQLite history, and more

Add backtesting engine, responsive design, and updated README

Add hyperparameter tuning, dark mode, CSV export, Docker, CI/CD

Phase 2: Configurable periods, feature importance, data caching

Phase 1: Stability & testing foundation

Add model ensembling with simple average, weighted average, and stacking

Add multi-model prediction platform with React frontend

added ARIMA Model future prediction

added linear regression future prediction

added future prediction