Release — carry explicit_model_pick through /goal (#6705) (#7114)

* fix(session): sync provider change mid-session (#6703)

* fix(session): full chat-start parity for /goal explicit-pick (#6703)

Addresses review parity details on #6703:
- stamp model_explicit_pick_signature after explicit goal resolution
  (both kickoff paths), matching /api/chat/start #5979, so a first /goal
  launch after a deliberate custom-provider pick survives a cold
  streaming catalog instead of reverting to the profile default
- consume the one-shot pending session-model marker in cmdGoal,
  matching the chat/start path (messages.js), so a later /goal with an
  unchanged dropdown isn't treated as an explicit pick

* fix(session): consume pending model-pick marker only after successful kickoff (#6705)

* fix(session): node-driven behavioral tests for /goal explicit-pick marker (#6703)

* changelog: #6705 — carry explicit_model_pick through /goal

* ci: re-trigger tests on fresh runners (prior run's shards hung on GitHub-hosted runners)

* ci: re-trigger (playwright browser-install hung on GH runners again; warm cache should restore)

---------

Co-authored-by: webtecnica <webtecnica@gmail.com>
Co-authored-by: n <a@n>
Co-authored-by: nesquena-hermes <nesquena-hermes@users.noreply.github.com>

CHANGELOG.md

@@ -5,6 +5,8 @@
 
 ### Fixed
 
+- **A `/goal` launch no longer silently switches providers mid-session after a deliberate model pick.** When a session had a deliberate cross-provider model/provider choice, running `/goal` omitted the `explicit_model_pick` marker that `/api/chat/start` sends, so the model resolver treated the persisted pick as stale and "repaired" it back to the profile default — silently changing providers while the goal ran. Both the frontend `/goal` command and the backend `_handle_goal_command` (initial kickoff and kickoff-prompt fallback paths) now carry the explicit-pick marker and stamp the pick signature, matching `/api/chat/start`; ordinary default sessions are unaffected (they still omit the marker, so a default pick stays repairable). Thanks @webtecnica. (#6705)
+
 - **A completed assistant turn no longer renders twice in the feed.** In `renderMessages()`, the live-turn preserve guard kept the in-flight assistant node across the DOM rebuild whenever it held any rendered content, so when a stream ended but its inflight bookkeeping was not yet cleared the just-completed turn was re-attached over the rebuilt settled transcript (a first copy without the model label, then a second with it). The stored data was always clean (state.db, sidecar, and `/api/session` each hold one row) — the duplicate existed only in the DOM. Preservation now requires a provable live owner (`S.activeStreamId` or explicit live-projection markers) instead of bare DOM content; the mid-stream flicker guard and blank-turn guard are preserved. Thanks @webtecnica. (#7109)
 
 - **Visible inline chat videos no longer appear stalled after metadata.** Every inline video stayed at `preload="metadata"`, so a currently-visible mobile player could look frozen because the browser stops loading after metadata. A shared IntersectionObserver now promotes a near-viewport video to `preload="auto"` (and immediately on play), keeps off-screen history videos at metadata to avoid buffering every historical video, and unobserves nodes removed before they intersect. No media URL, caching, or controls change. Thanks @allenliang2022. (#7076)