Name the device that returns audio, not the one that did not (V-487)

docs/deployment.md still told the next reader the microphone was the fifine on
card 0. Three days of silence started there, so the paragraph now carries the
levels and the check that finds it: stop the unit, arecord five seconds,
measure. A live room floor reads near 0.001.

docs/deployment.md

@@ -166,9 +166,21 @@ the GPU. A model that will not load is logged and not fatal.
 `-barge-in` is not passed. The threshold is room-specific and this room has no
 number yet. Read the "suppressed while speaking" means out of the journal first.
 
-The device is `plughw:0,0` and not `hw:0,0`. The fifine offers 2 channels at
-44100 or 48000 and nothing else, and mavwaked asks arecord for 16kHz mono. Bare
-`hw` dies on "Channels count non available" before a frame is read.
+The device is `plughw:CARD=Gen,DEV=0`, the Scarlett Solo. It is `plughw` and
+not `hw` because mavwaked asks arecord for 16kHz mono. No microphone here
+offers that, so bare `hw` dies on "Channels count non available" before a
+frame is read. It is named `CARD=Gen` and not card 4 because a USB card number
+moves when something else is replugged.
+
+It used to be the fifine on card 0, and that cost three days. mavwaked logged
+zero completed utterances across them, before the wake word existed and after.
+The fifine returns RMS 0.00004 with its capture switch on and its ALSA volume
+at the full 496 of 496. That silence is in the hardware and no flag reaches
+it. Over the same eight seconds of speech the onboard ALC897 read 0.142 and
+the camera 0.289, both clipping at peak 1.0. The Scarlett read 0.003 clean.
+
+Check the level before blaming the gate. Stop the unit, run `arecord` against
+the device for five seconds, and measure. A live room floor reads near 0.001.
 
 The three `-wake-` flags require the keyword "Мэйвен" (V-487 stage two). Drop
 them and the loop runs open, which is what it did before. The threshold is the