## Why
Trimming interleaved realtime transcripts by utterance order can discard the latest speech from an earlier utterance. Evicting after each delta can also drop one speaker before the other speaker's delta from the same frame arrives, losing recent instructions at handoff.
## What changed
Use raw frame recency to trim timed frameless bidirectional transcripts within the 8 KiB budget. Defer eviction until the frame advances or the transcript is consumed, and retain both speakers' suffixes when they share the newest frame. Preserve conversation order and fall back to FIFO eviction when timing is unavailable.
Track trimmed prefixes so final transcripts can extend retained speech without making delayed finals appear newer.
## Testing
Add regression coverage for frame recency, same-frame event ordering, UTF-8 truncation, delayed finals, and untimed fallback. Add an app-server handoff test verifying that both speakers' recent speech and the latest user instruction survive while live transcript notifications remain unchanged.
GitOrigin-RevId: b01b729d8bdd4acb26e0385442ce40819355deac
## Why
Interleaved speaker transcripts can fragment handoff context, and delayed final transcripts can overwrite newer speech.
## What changed
- Reconcile V3 transcript deltas and finals with the latest entry for the same speaker.
- Replace accumulated text only when the final transcript extends it, preserving newer speech when a final arrives late.
- Start a new entry after each completed utterance, keeping repeated speech and final-only turns distinct even when empty deltas arrive.
- Preserve live transcript notifications and legacy protocol behavior.
## Testing
Add unit coverage for interleaved speakers across reconnects, either completion order, repeated utterances, final-only turns, and empty deltas. Add app-server integration coverage for expanded and delayed finals, checking live notifications and reconciled handoff context.
GitOrigin-RevId: 961729281f61b95fd3e0c5cc3ec72512987980b3
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