fix(firmware): don't let the feedback gong swallow return-to-idle

A spoken volume command left the face stuck in the thinking spinner. The
gateway sends state:thinking -> command -> state:idle, but the device's
state:idle handler is gated on !audio_is_playing(), and the feedback gong
had been setting s_playing for its (up to 5 s) duration — so the idle was
ignored and nothing re-sent it. The gong is a UI cue, not reply playback,
so it no longer sets s_playing. This also drops the 5 s wake-gate the gong
was imposing.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LKPbR6DY2JygHbyLjxm7Uu

CHANGELOG.md

@@ -8,6 +8,12 @@ until the first tagged release.
 
 ## [Unreleased]
 
+### Fixed
+
+- A spoken volume command no longer leaves the face stuck in the thinking
+  spinner — the feedback gong is a UI cue and no longer holds the busy state,
+  so the return-to-idle isn't swallowed.
+
 ## [0.2.0] — 2026-07-15
 
 ### Added

firmware/main/audio.c

@@ -161,8 +161,10 @@ static void audio_task(void *arg)
          * returns, preventing a playback-boundary false wake. */
         if (job == JOB_GONG && s_gong != NULL) {
             /* Play in chunks so a new request (a fresh volume change) cuts the
-             * current gong off and restarts, instead of queueing another 5 s. */
-            s_playing = true;
+             * current gong off and restarts, instead of queueing another 5 s.
+             * Note: the gong is a UI cue, not "playback" — it deliberately does
+             * NOT set s_playing, so a following state:idle isn't swallowed (that
+             * guard is for reply audio) and it doesn't gate wake for 5 s. */
             uint32_t gen;
             do {
                 gen = s_gong_gen;
@@ -172,7 +174,6 @@ static void audio_task(void *arg)
                     esp_codec_dev_write(s_spk, s_gong + off, n * sizeof(int16_t));
                 }
             } while (s_gong_gen != gen);   /* a new request arrived mid-play → restart */
-            s_playing = false;
             s_gong_active = false;
         } else if (job == JOB_CHIME && s_chime != NULL) {
             s_playing = true;