The capture-silence fix metered the mic pull by wall-clock, but the mic fills
the bridge at its own device clock. Over a long silent stretch they drifted, the
bridge backed up to its 0.5s cap and dropped oldest samples -> the recording
skipped/'fast-forwarded' late in the gap. And a 10ms idle threshold punched
silence into the loopback on brief inter-packet stalls -> audible ticks. Now:
drain the whole bridge (device-paced, no overflow) and only synthesize after a
sustained 150ms gap.