* perf(media): preload visible chat videos
* fix(media): ignore detached visibility callbacks
* fix(ui): require provable live owner for live-turn preservation (#6948)
A completed assistant turn could render twice: when the stream ended
(S.activeStreamId cleared) but INFLIGHT[sid] was not yet cleaned, the
preserve guard treated bare rendered content (.msg-body presence) as
proof of liveness and re-attached the stale live DOM node OVER the
rebuilt settled transcript — a second copy of the same message. Data
was always clean (state.db, sidecar, /api/session each hold one row);
the duplicate existed only in the rendered DOM.
Preserve the live turn across the wipe only while there is a provable
live owner: an active stream (S.activeStreamId, the #3877 mid-stream
case) or explicit live-assistant evidence in the current message
projection (S.messages carrying a client-side _live / _activityBurstId /
_liveSegmentSeq marker — the reconnect/terminal-projection case). A
settled transcript has neither, so the durable settled render wins and
appears exactly once. The #5390 blank-turn guard (对话消失) is preserved:
a dead empty shell has no live projection either and is still dropped.
* changelog: exp batch — #7109 double-render fix + #7076 video preload
---------
Co-authored-by: allenliang2022 <allenliang2022@users.noreply.github.com>
Co-authored-by: webtecnica <webtecnica@gmail.com>
Co-authored-by: n <a@n>
Co-authored-by: nesquena-hermes <nesquena-hermes@users.noreply.github.com>
