Please allow the SQ AI Chat Assistant Demo to work with asset classes other than equities

Specifically:

• Enable back-testing and data look-ups for major forex pairs (e.g., EUR/USD, GBP/USD, USD/JPY), Metals,etc.
• Add support for leading indices (e.g., S&P 500, NASDAQ-100, Dow Jones, Nikkei 225).
• Expose these symbols through the same UI and API endpoints currently used for stocks.

Broadening coverage to multiple asset classes will let users build and validate more diverse strategies and better reflects real-world trading needs.