feat: For steppir & Ultrabeam,possibility to change each element length

internal/ultrabeam/ultrabeam.go

@@ -470,6 +470,27 @@ func (c *Client) queryProgress() ([]int, error) {
 	return []int{total, current}, nil
 }
 
+// ReadElements reads the current per-element lengths for the active band
+// (CMD_READ_BANDS). The controller is write-only for ModifyElement, so this is
+// the only way to see the current lengths — needed so the operator isn't
+// adjusting blind. The reply payload layout is not documented in the code, so we
+// LOG it verbatim (once) and parse a best guess: element lengths as 16-bit
+// little-endian values, matching how ModifyElement WRITES a length. Confirm the
+// format from the logged bytes on real hardware, then tighten the parse.
+func (c *Client) ReadElements() ([]int, error) {
+	payload, err := c.sendCommand(CMD_READ_BANDS, nil)
+	if err != nil {
+		return nil, err
+	}
+	log.Printf("Ultrabeam: READ_BANDS payload (% X) — %d bytes", payload, len(payload))
+	// Best-guess parse: consecutive 16-bit LE values = element lengths in mm.
+	out := make([]int, 0, len(payload)/2)
+	for i := 0; i+1 < len(payload); i += 2 {
+		out = append(out, int(payload[i])|int(payload[i+1])<<8)
+	}
+	return out, nil
+}
+
 // SetFrequency changes frequency and optional direction (command 3)
 func (c *Client) SetFrequency(freqKhz int, direction int) error {
 	// Trace WHO asked for the change — the caller's function + line — so an