Capture source audio before priority turn-boundary queues

When a recording callback closes a turn on a priority stop signal, queued audio data may arrive afterward and disappear from the turn recording even though the full track contains it. Test the actual recorder placement with native queued frames before trusting utterance clips. For generated-speech diagnostics, capture context-tagged PCM at the existing synchronous source hook before downstream queues, preserve request completion and error evidence, and keep delivery verification separate. This establishes generated audio only; it does not prove caller playback or text association.

Applies when: asynchronous voice pipelines use different priorities for control signals and audio data. Keywords: audio recording priority queue turn stop source capture completion playback