Release final speech with native gap events and separate reply gates

Final recognized words and an ended speaker turn are separate events. A caller that waits only for one end-of-speech flag can remain silent even after complete words arrive. When the recognizer exposes a native word-gap end event, use it to release accumulated final words, while rejecting stale, duplicate, or empty endpoints. Keep reply eligibility separate: a pause inside a compound question must not release a recording that answers an unfinished question. The fallback fixes turn release, not intent understanding, and needs actual recordings with the missing flag plus tests of normal endpoints.

Applies when: Streaming speech recognition drives automated recorded replies. Keywords: final words speech flag word gap endpoint silence compound questions