A visible tab can permanently miss a server-initiated turn (self-wake /
cron / restart hook) when its per-session SSE is momentarily down at the
emit instant. server_turn_started is a fire-and-forget broadcast with no
replay buffer; if the turn also finishes before the tab reconnects, the
on-subscribe self-heal finds no live run in ACTIVE_RUNS and replays
nothing, so the transcript stays stale until a hard refresh.
Extend the self-heal: the (re)subscribing tab reports its last-known
message_count (?known_count); when there is no live run to replay, the
handler compares the persisted count and, if the server is ahead, emits a
lightweight session-updated frame. The frontend syncs incrementally via
the #5189 keepStaleUntilLoaded swap-in-place loadSession path (no
clear+refetch, so the #5177/#5189 blank-gap jump is not reintroduced).
Idle-only and pane-scoped; emits only when the server is strictly ahead.
* stage bg_task trio combined (#2979 superset) on master for deep review
* fix(bg_task): unsubscribe SessionChannel on header-write failure (Codex deep-review catch) + regression test
* test: realign on-subscribe-recovery anchor to subscribe_to_session_channel after leak fix
* CHANGELOG: bg_task trio as v0.51.340 LD (HELD pending independent review)
* bg_task trio: apply 3 independent-review (greptile) fixes
1. start_session_turn now threads the session PROFILE model defaults
(_read_profile_model_config) into the wakeup model-resolve, so a brand-new
session with an empty model falls back to the profile default not global
DEFAULT_MODEL. Updated the white-box spy test signature accordingly.
2. /api/session/stream omits the Connection header (HTTP/1.1 keep-alive
default) to match the #3103 long-lived-SSE pattern.
3. Reaper now prunes _LAST_EMIT_TS for collected sessions so the coalesce
timestamp map can't grow one permanent entry per session forever.
nesquena APPROVED the PR; these are the 3 non-blocking greptile suggestions.
* test: realign _start_session_turn adapter stub lambda to new profile-defaults signature
