Adds a Print button to OMNY_SampleStorage that renders an A4 PDF
replica of the on-screen stage/gripper/magazine grid (via
bec_lib.pdf_writer.PDFWriter) and sends it to the local CUPS queue
WSLA_X12SA via `lp`. Checks printer availability with a quick local
`lpstat` query first, so a host without that queue gets a plain
"printer not available" message instead of a raw CUPS error; the
actual `lp` call still offers Retry/Ignore on failure, mirroring the
existing P-touch label-print fail-soft pattern.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BgQoxFiJRZi1FnmnF8epKh
