label_printer.py renders a DK-11221 23x23 mm label (QR code linking
to the lamp's buildfor.life page plus the ID) and sends it over the
network backend (brother-ql-next). The station prints two after each
successful measurement, one for the box and one for the lamp; printer
failures never lose a run, and any lamp can be reprinted with
uv run label_printer.py <ID>. Printer address via HPCS_LABEL_PRINTER
or --printer.
