Adds four trace points on the listener pipeline so an end-to-end JSONL
capture (`adb logcat -s NestsTraceJsonl:D -v raw > nest-trace.jsonl`)
shows wall-clock latency at every stage:
frame_received (MoqLiteSession.drainOneGroup, after trySend)
frame_object_mapped (MoqLiteNestsListener.wrapSubscription map)
pcm_decoded (NestPlayer.play, after decoder.decode)
pcm_enqueued (NestPlayer.play, after player.enqueue)
Each event carries (sub_id, group_seq, ...) or (track_alias, obj_id, ...)
so the same frame can be followed through all four stages. Deltas
isolate which segment owns the observed startup-only ~1s lag:
subscribe_send → first frame_received : relay forward latency
frame_received → pcm_decoded : Opus decode wall-time
pcm_decoded → pcm_enqueued : AudioTrack ring backpressure
pcm_enqueued → next pcm_decoded : decode-loop scheduling
Tracing auto-enables on debug builds when `NestActivity` opens and
disables on `onDestroy` so release apps pay only the field-load
guard inside `NestsTrace.emit`. Capture instructions are inline at
the call site in `NestActivity.onCreate`.
Claude
86c66920d3