PMax Channel Distribution Alert

This script analyses how advertising spend is distributed across Display, Video, Shopping, and Search channels within each Performance Max campaign. It compares rolling averages (default 7 days) against longer periods (default 30 days) to detect meaningful shifts in channel performance. When significant changes exceed the configured threshold, it sends detailed email alerts with campaign-specific breakdowns and provides a comprehensive spreadsheet with historical data for further analysis. Key features: - Per-campaign channel distribution monitoring - Rolling average vs long-term comparison - Cost-focused alerts (most actionable metric) - Automated email notifications with campaign breakdowns - Detailed spreadsheet export with color-coded channel data - Configurable thresholds and time periods