zebra-report: deploy sink-reapply on attach + per-tick ctx.sink telemetry

Continues ticket 0001 fix. Fox 2026-06-07 second telemetry pass showed
blanka-chrome's audioCtx sink reverted to 'default' after a leave/rejoin
even though the user had a picked device, because applySinkToAudioCtx
only ran inside the `if (!audioCtx)` branch and a persistent ctx with a
drifted sinkId stayed default forever.

Attach now re-applies sink when audioCtx exists + speakerDeviceId is set
+ ctx.sinkId differs. Per-tick telemetry exposes ctx.sink= (and want= on
mismatch) so the next session can verify sink stays on the picked device
across leave/rejoin.

Source commit: 4cedd85 in zebra-report.git

zebra-report/zebra-spaces.html

@@ -3281,6 +3281,19 @@ function attachAudioStreamViaWorklet(uuid, stream, targetSeconds){
       applySinkToAudioCtx();
     }
     catch(e){ logLine('err','audioCtx create: '+e.message); return false; }
+  } else if (speakerDeviceId
+             && typeof audioCtx.setSinkId === 'function'
+             && audioCtx.sinkId !== speakerDeviceId){
+    /* audioCtx survived a leave→re-enter but its sinkId drifted back
+     * to '' (system default). Re-apply the picked sink so the worklet
+     * keeps emitting to the device the user picked in the dropdown.
+     * Fox 2026-06-07 blanka-chrome telemetry: first attach
+     * `sink=c38572ec…`, a leave/rejoin later, next attach
+     * `sink=default` and no `audioCtx sink → …` success line —
+     * applySinkToAudioCtx only ran inside the `!audioCtx` branch above,
+     * so a persistent audioCtx with reset sinkId stayed default
+     * forever. Idempotent: same-sink call is a noop. */
+    applySinkToAudioCtx();
   }
   if (audioCtx.state === 'suspended'){
     audioCtx.resume().catch(()=>{});
@@ -5830,6 +5843,23 @@ async function dumpTelemetry(){
   /* reset per-tick whisper counters */
   _whisperTick.sent = 0; _whisperTick.dropped = 0;
   _whisperTick.emitted = 0; _whisperTick.totalLatencyMs = 0;
+  /* audioCtx sink visibility on EVERY tick — the one-shot 'sink=…' in
+   * the attach log only captures the moment of attach; if the sink
+   * drifts later (Chrome's audioCtx.sinkId getter can revert to '' on
+   * device-changes, leave/rejoin, suspend/resume), this surfaces it
+   * every 5s instead of needing to grep for the rare attach event.
+   * Fox 2026-06-07 blanka-chrome: per-attach sink looked fine but the
+   * silent-listener state persisted because the GETTER value drifted
+   * between attaches. */
+  if (audioCtx){
+    const cs = (audioCtx.sinkId === undefined) ? 'n/a'
+             : (audioCtx.sinkId || 'default');
+    const want = speakerDeviceId || 'default';
+    parts.push('ctx.sink=' + (cs.length > 12 ? cs.slice(0,8) : cs)
+               + (cs !== want && audioCtx.sinkId !== undefined
+                  ? ' want=' + (want.length > 12 ? want.slice(0,8) : want)
+                  : ''));
+  }
   /* receiver stats from sfuSubPC (the main listener path) */
   if (sfuSubPC && typeof sfuSubPC.getStats === 'function'){
     try {
@@ -8183,8 +8213,8 @@ logLine('', 'ready — pick a handle, type a rendezvous code, enter the space');
 
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