Pin the keyword models to one thread each and ship them (V-487)

The gate loaded and worked on workpc and took mavwaked from 68% of one core
to 335%. onnxruntime sizes its intra-op pool to every core and spins between
runs, which an always-on gate scoring three graphs twelve times a second
provokes for the whole day. One thread per session brings it to 81%, so the
keyword costs about 13% of a core, and each graph still finishes well inside
its 80ms.

The unit now passes the three -wake- flags and the models sit beside
silero_vad.onnx in ~/.local/share/maven/models. The threshold is left at the
binary's default so there is one place to change it.

deploy/mavwaked.service

@@ -4,11 +4,22 @@
 # user unit because it needs his ALSA session and his ssh agent, and because
 # it should stop when he logs out.
 #
-# THERE IS NO WAKE WORD YET (V-487 stage two). Anything spoken near the fifine
-# becomes a turn. What makes that safe rather than expensive is voiceSender:
-# it sends Surface=SurfaceVoice, which caps every command at L0, so no
-# accidental trigger runs a destructive act. It does not stop her answering
-# out loud, so this unit is his to stop when the room is not his alone.
+# The keyword is "Мэйвен" and the three -wake- flags are what require it
+# (V-487 stage two). Without them anything spoken near the fifine becomes a
+# turn, which voiceSender makes safe rather than expensive: it sends
+# Surface=SurfaceVoice, capping every command at L0. That does not stop her
+# answering out loud, which is the whole reason the keyword exists.
+#
+# The threshold is 0.999 and it is the binary's default, so it is not passed.
+# It came from 65 minutes of held-out Russian speech through this same binary:
+# 0.9 false wakes an hour against 2.8 at 0.99, for one lost render out of 126
+# (docs/evals/2026-08-09-wake-word.md). If the room proves noisier than the
+# corpus, read the scores out of this unit's journal and pass -wake-threshold.
+# Do not lower it by guessing.
+#
+# A keyword shorter than 1.32s can be heard too late to be used, because the
+# head scores 1.28s of audio and the VAD has closed the utterance by then.
+# "Мэйвен, <request>" is unaffected. A bare "Мэйвен" is the case that fails.
 #
 # -vad-model is passed on purpose. Silero answers "is this frame speech" where
 # the energy floor answers "is this frame loud". It declines white noise at
@@ -24,7 +35,7 @@
 #            systemctl --user enable --now mavwaked.service
 
 [Unit]
-Description=Maven always-on listening (VAD, no wake word yet)
+Description=Maven always-on listening (silero VAD, "Мэйвен" keyword)
 # The tunnel is the only path to mavend and the only thing authenticating it.
 Requires=maven-voice-tunnel.service
 After=maven-voice-tunnel.service
@@ -45,6 +56,9 @@ ExecStart=%h/.local/bin/mavwaked \
   -addr 127.0.0.1:9100 \
   -lang ru \
   -vad-model %h/.local/share/maven/models/silero_vad.onnx \
+  -wake-model %h/.local/share/maven/models/maven_wakeword.onnx \
+  -wake-mel %h/.local/share/maven/models/melspectrogram.onnx \
+  -wake-embed %h/.local/share/maven/models/embedding_model.onnx \
   -onnx-lib %h/.local/lib/libonnxruntime.so
 Restart=on-failure
 RestartSec=5