Connect to the CYD (ESP32-2432S028) board over Web Serial (CH340/CP2102 USB-UART bridge), choose a key index, fetch a pubkey, sign a kind 1 event, and test NIP-04 / NIP-44 encrypt + decrypt RPCs.
Requirements: Chrome 89+, Edge 89+, or Brave. Web Serial is not available in Firefox or Safari. Linux users: Add yourself to the dialout group (sudo usermod -aG dialout $USER) and replug the device. Windows users: Install the WCH-IC CH340 driver if the port does not appear. Note: Close any serial monitor (Arduino IDE, idf.py monitor) before connecting — only one app can hold the port at a time.