remote panic button, exit trades from phone — tradovate auto-cancel

Added a remote panic button to the Tradovate auto-cancel extension. A mobile-friendly page (deployed on Netlify) shows live positions from Firestore and lets you tap to trigger "Exit at Mkt & Cxl" on your laptop from your phone. Uses Google Auth for security, confirm dialog to prevent fat-fingers, supports multiple instruments in a 2-column grid with individual or exit-all. Extension polls Firestore every 3 seconds, pushes position data every 5 seconds. Zero cost on Firebase/Netlify free tiers.