Replace the OpenCV motion-detection daemon with a fido2-token -L check —
presence now means "a FIDO2/U2F key is plugged in", queried without any
touch/tap. Adaptive poll: 20s under light load, 120s under moderate,
600s under heavy. Drops the old motion "grace window" since key presence
doesn't flicker like camera motion did.
Removes presence_detect.py, the presence camera config/test flow from
enroll-biometrics.sh, and the python-opencv dependency (kept v4l-utils,
still used by howdy's camera setup). Adds a standalone presence-test.sh
instead of folding the FIDO check into enroll-biometrics.sh's dialog TUI —
there's nothing to enroll, so it doesn't belong in that flow.
Amir Alexander Abdelbaki