docs(changelog): v2.6.9-warm-acp

CHANGELOG + roadmap (through v2.6.9) + openspec v2-6 Phase 2 checked off (2.1-2.4; Smoke 2/2b pending live).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

openspec/changes/v2-6-persistent-agent-sessions/tasks.md

@@ -40,16 +40,14 @@ ACP follows; hardening last.
 - [ ] **Smoke U:** stage edits with opencode then boocode → DiffPanel badges each row to the
       right agent; composer shows "resumed" when re-selecting opencode, "new session" for goose. *(pending live frontend deploy — Docker container rebuild)*
 
-## Phase 2 — Warm ACP backend (goose, qwen) — ⬜ REMAINING
+## Phase 2 — Warm ACP backend (goose, qwen) — ✅ SHIPPED `v2.6.9-warm-acp` (Smoke 2/2b pending live)
 
 > **Lift (design §10):** `qwen --acp` is a validated reference (real stdio multi-session, `loadSession`/resume) — wire qwen into the existing `acp-dispatch.ts` stack. **goose ACP has no `loadSession`/resume** → cross-restart resume needs a different design (re-`session/new` + accept memory loss, or replay). Cross-check qwen `@agentclientprotocol/sdk@^0.14` vs BooCode `^0.22` before relying on `unstable_resumeSession`. Do **qwen first** to de-risk.
 
-- [ ] 2.1 `backends/warm-acp.ts`: persistent spawn + `ClientSideConnection`; `initialize` +
-      `session/new` once; reuse `acp-dispatch.ts` `handleSessionUpdate`.
-- [ ] 2.2 `prompt`: `session/prompt` on the warm connection per turn; per-turn abort signal only.
-- [ ] 2.3 Child supervision: detached lifetime, exit handler marks `status='crashed'`.
-- [ ] 2.4 Dispatcher routes `goose`/`qwen` to warm backend; keep one-shot fallback for arena/MCP
-      (or opt those into pool too — decide in review).
+- [x] 2.1 `backends/warm-acp.ts` `WarmAcpBackend` — persistent spawn + `ClientSideConnection`; `initialize` + `session/new` once per `(chat,agent)`. `handleSessionUpdate` extracted to a shared pure `acp-event-map.ts` (one-shot path byte-identical).
+- [x] 2.2 `prompt`: `session/prompt` on the warm connection per turn; abort = `session/cancel` the prompt only (never kills the child).
+- [x] 2.3 Child supervision: pool-owned lifetime; `exit` marks `agent_sessions.status='crashed'` → re-spawn next turn.
+- [x] 2.4 Dispatcher routes `goose`/`qwen` chat-tab tasks to the warm backend via pure `shouldUseWarmBackend(task)` (needs `session_id`+`chat_id`); one-shot `runExternalAgent` fallback kept for arena/MCP/`new_task`. *(SDK note resolved: installed `@agentclientprotocol/sdk@^0.22.1` has stable `resumeSession`/`loadSession`; resume moot in the warm hot path, deferred to Phase 3.)*
 - [ ] **Smoke 2:** two messages in a goose chat reuse the same process + ACP session + worktree;
       reasoning still renders; no per-turn respawn.
 - [ ] **Smoke 2b (switch round-trip):** opencode → boocode → opencode in one chat — opencode
@@ -99,7 +97,7 @@ ACP follows; hardening last.
 
 1. ~~**F.1 interrupt-bug fix**~~ — ✅ shipped `v2.6.7-interrupt-guard` (3 regression tests, TDD).
 2. ~~**Phase 1-UX** (U.1–U.6)~~ — ✅ shipped `v2.6.8-agent-attribution` (3 parallel agents, disjoint files; 9 new tests). Smoke U pending the frontend Docker rebuild.
-3. **Phase 2 — warm ACP, qwen first then goose** — qwen has a validated `--acp` reference; goose's missing resume is the open design question, so qwen de-risks the pattern. Smoke 2 + 2b (the switch round-trip success criterion).
+3. ~~**Phase 2 — warm ACP, qwen first then goose**~~ — ✅ shipped `v2.6.9-warm-acp` (15 new tests; one-shot path preserved). Smoke 2 + 2b pending live exercise post-deploy.
 4. **Phase 3 — lifecycle hardening** — lift openchamber's state machine; do crash-recovery (3.1/3.2/3.6) + worktree reaper (3.3/3.4 + LRU) together (shared supervision loop). Closes the two ⬜ success criteria (server-crash recovery, close→cleanup).
 5. **Tests T.1–T.3 + `BOOCODER.md` (D.1 remainder)** — backfill alongside each phase, not at the end.