Replace the dual-switch handler with one button: short press cycles
patterns, long press arms deep sleep with ext1 GPIO wake. Add a
heartbeat LED task and fix the IMU test I2C pins to GPIO21/GPIO6.
Co-authored-by: Cursor <cursoragent@cursor.com>
Wire LSM6DS3 readings into the runtime telemetry stream, expose them over web endpoints, and render live voltage/IMU data in the dashboard with websocket updates.
Made-with: Cursor
