Switch to IPv4 zeroconf, add test framework with discovery test, fix serial enumeration

lib/client/client.go

@@ -92,3 +92,7 @@ func (c *Client) PICOBOOT() error {
 func (c *Client) Info() (*ResponseInfo, error) {
 	return roundTrip[ResponseInfo](c, &RequestInfo{})
 }
+
+func (c *Client) Test(name string) (*ResponseTest, error) {
+	return roundTrip[ResponseTest](c, &RequestTest{Name: name})
+}