UAT US14/US5: firmware choreography & security sweep servos don't move #166

Symptom. Scripted physical motion doesn't execute, even though the state/audio/event
layers fire correctly. Idle-motion head glances DO work, so it's choreography/sweep-specific.

Evidence.

• US14 dance: Dance mode: macarena streams audio, but no state_changed → dance,
  no _handle_dance, no rainbow ring, no body movement. Resolves via song-playback path only.
• US5 security: state_changed → security + security_pose scan_start emitted, capture
  loop started, photo taken — but the yaw sweep (−500→+500→0) never executed.

Expected. Dance runs choreography + rainbow ring; security performs the yaw sweep.

Log excerpt.

20:04:02 Dance mode: macarena / streaming singing audio macarena.mid   # no state_changed->dance
20:07:14 event state_changed -> security ; event security_pose scan_start   # but no physical sweep

Note. US14 "didn't move this time" suggests possible intermittency. audio_capture_pending
in the security loop is the known #31 pending, not part of this issue.

Video verification (2026-07-11 phone recording IMG_1295.MOV, starts 19:41:32).

• Dance window: frames at 20:04:04 / 20:04:12 / 20:04:22 show the head and body in an
  identical pose across 18 s while the mouth/speech-bubble animates — audio playing,
  zero choreography, no rainbow ring visible.
• Security window: frames at 20:07:17 / 20:07:28 / 20:07:38 show the camera-capture view
  then a return to the neutral face with no yaw change across 21 s — capture loop ran,
  sweep didn't.
• Nuance preserved: for dance there is no state_changed → dance in any log, so the
  firmware dance state may never have been entered (event emission vs state entry is
  unresolved without serial capture); for security the state was entered and the pose
  event emitted, yet the sweep still didn't run. Two distinct failure layers.

From the filmed UAT session 2026-07-11 (uat-sessions/2026-07-11/: results.csv, container logs, two video recordings). Investigated and drafted with AI assistance (Claude Fable 5 via Claude Code); human-reviewed before filing.