Use nonblocking AudioRecord reads with data and timestamp deadlines. Serialize idempotent close, finish interrupted joins before release, isolate callback failures, and abort stereo fallback when partial-record cleanup fails.
Close failed shared readers to new subscriptions, roll back worker startup, isolate observers, preserve interrupt state, and release the last consumer exactly once. Add an independent capture-tests JVM module to the standard Android unit-test task.
Validation: 38 capture scenarios (25 AudioRecord plus 13 PCM/PTT), 455 JVM tests, assembleDebug, core build, and full check.sh (225 tests plus proxy/burst/load) passed.
evgeny