feat: refactor sgclaw around zeroclaw compat runtime

third_party/zeroclaw/docs/hardware/datasheets/arduino-uno.md

@@ -0,0 +1,37 @@
+# Arduino Uno
+
+## Pin Aliases
+
+| alias       | pin |
+|-------------|-----|
+| red_led     | 13  |
+| builtin_led | 13  |
+| user_led    | 13  |
+
+## Overview
+
+Arduino Uno is a microcontroller board based on the ATmega328P. It has 14 digital I/O pins (0–13) and 6 analog inputs (A0–A5).
+
+## Digital Pins
+
+- **Pins 0–13:** Digital I/O. Can be INPUT or OUTPUT.
+- **Pin 13:** Built-in LED (onboard). Connect LED to GND or use for output.
+- **Pins 0–1:** Also used for Serial (RX/TX). Avoid if using Serial.
+
+## GPIO
+
+- `digitalWrite(pin, HIGH)` or `digitalWrite(pin, LOW)` for output.
+- `digitalRead(pin)` for input (returns 0 or 1).
+- Pin numbers in ZeroClaw protocol: 0–13.
+
+## Serial
+
+- UART on pins 0 (RX) and 1 (TX).
+- USB via ATmega16U2 or CH340 (clones).
+- Baud rate: 115200 for ZeroClaw firmware.
+
+## ZeroClaw Tools
+
+- `gpio_read`: Read pin value (0 or 1).
+- `gpio_write`: Set pin high (1) or low (0).
+- `arduino_upload`: Agent generates full Arduino sketch code; ZeroClaw compiles and uploads it via arduino-cli. Use for "make a heart", custom patterns — agent writes the code, no manual editing. Pin 13 = built-in LED.