A comprehensive YouTube KOL discovery and analysis system for product marketing. Use this skill when users need to (1) Search and discover YouTube channels (KOLs) by keywords, (2) Analyze channel metrics (subscribers, views, engagement rates), (3) Detect channel language and video content language, (4) Use AI (Deepseek/Zhipu) to evaluate channel-product fit for marketing campaigns, (5) Export analysis results to Excel with multiple sheets, (6) Deploy a Docker-based web system with real-time progress tracking on Synology NAS or other servers, (7) Manage YouTube API keys with automatic rotation and quota tracking, (8) Support incremental updates to track new channels over time.