Replace load.sh with Go program

lib/picoserial/picoserial.go

@@ -0,0 +1,35 @@
+package picoserial
+
+import (
+	"fmt"
+
+	"go.bug.st/serial"
+	"go.bug.st/serial/enumerator"
+)
+
+func FindDevice() (string, error) {
+	ports, err := enumerator.GetDetailedPortsList()
+	if err != nil {
+		return "", fmt.Errorf("enumerating ports: %w", err)
+	}
+	for _, p := range ports {
+		if p.IsUSB {
+			return p.Name, nil
+		}
+	}
+	return "", nil
+}
+
+func SendByte(portName string, b byte) error {
+	port, err := serial.Open(portName, &serial.Mode{BaudRate: 115200})
+	if err != nil {
+		return fmt.Errorf("opening %s: %w", portName, err)
+	}
+	defer port.Close()
+
+	_, err = port.Write([]byte{b})
+	if err != nil {
+		return fmt.Errorf("writing to %s: %w", portName, err)
+	}
+	return nil
+}