🧪 Add tests and improve YouTube scraper

✨ Switch to YouTube Data API for reliable video search

Fix Gradio startup: Set app_file to app.py in README

Fix Gradio startup with better error handling and API key validation

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Document FAISS as optional with upload instructions

Add missing router and orchestrator modules for multi-agent architecture

Fix: Remove unused data_fetchers import

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Add multi-agent coach system (FAISS files to be uploaded separately)

initial commit