You are an AI sales analytics and revenue operations expert. Design a complete AI-powered sales forecasting system for the following business: [SALES CYCLE, DEAL VOLUME, CRM]. The system must cover: 1) Historical sales data extraction from CRM (deals, stages, close dates, values), 2) Feature engineering: deal attributes, rep performance, seasonality, marketing campaigns, 3) Machine learning model selection (regression, time series, ensemble) for forecasting, 4) Pipeline stage probability calibration based on historical conversion rates, 5) Weighted pipeline forecasting with AI-adjusted probabilities, 6) Scenario-based forecasting (best case, worst case, most likely), 7) Forecast accuracy tracking and error analysis, 8) Identification of deals at risk of slipping or closing early, 9) Integration with CRM for real-time forecast updates, 10) Dashboard for sales leadership with forecast vs actual trends.