Adds tools/check-audio.py and wires it into the gate as 'audio profiles',
advisory: a card pinned to Pro Audio is a preference, not a reason to refuse a
launch, but it IS the reason pavucontrol offers no Speaker / Headphones / HDMI.

The ranking is a faithful port of WirePlumber's own findBestProfile, including
its refusal to ever select pro-audio -- without that, a card someone pinned
there would read as correctly set.

--fix counts the sinks it would leave behind and stops at zero. On this box the
textbook repair (clear the pin, take WirePlumber's pick) would have switched off
the only four sinks present, since the laptop codec is pinned off and the USB
interface is unplugged. A fix that trades a wrong profile for no audio is not a
fix, and the fence has a test with that case in it.

Also records a finding the write-up turned up: the config fragment in
~/.config/wireplumber/wireplumber.conf.d/ is 0.5 format on an 0.4.17 install, so
neither it nor the DMIC guard written alongside it in July has ever been in
force. The tool flags that class -- a file that looks exactly like protection
and does nothing.