Codex ship-gate (CORE): _handle_session_anchor_scene loaded the session via
_get_or_materialize_session (by-id, no profile scoping) and persisted
anchor_activity_scenes without the active-profile visibility check GET /api/session
applies — an authenticated request under profile A could write anchor scenes onto a
profile-B session. Add the _session_visible_to_active_profile guard (404, no write),
mirroring routes.py:~8922. Regression test verified red-without/green-with the guard.
Co-authored-by: franksong2702 <franksong2702@users.noreply.github.com>
franksong2702's activity_scene_v1 anchor-scene model: live-stream/settled/refresh/re-entry
show the same ordered turn. Rebased clean (no conflicts) onto current master.
Co-authored-by: franksong2702 <franksong2702@users.noreply.github.com>
