docs(ai): refresh handoff state after PR #153 merge

- CURRENT_TASK rolls forward — PR #153 closed out, no active task,
  with recommended next moves (promote e2e gate to required, pick
  from TODO).
- HANDOFF rewritten — new home position is `main`; documents the
  e2e job's stub ANTHROPIC_API_KEY convention so future
  AI-touching e2e tests know what to expect.
- SESSION_LOG entry extended with the CI env-var diagnosis, the
  fix, the merge, and pointers to the natural next pickups.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.ai/CURRENT_TASK.md

@@ -1,28 +1,20 @@
 # CURRENT_TASK.md
 
-**Task:** Land PR #153 — fix the AssistantChatPage prefill `currentChatRef` bug that silently dropped AI follow-up responses in the task lane.
+**Task:** No active task — pick from [`TODO.md`](TODO.md).
 
-**Status:** in-progress (CI running on rebased branch)
+**Status:** ready for next pickup.
 
-**Definition of Done:**
-- [ ] PR #153 (`fix/tasklane-prefill-ref`) CI green on the rebased SHA `1559feb`. Backend, frontend, and e2e all pass.
-- [ ] PR #153 merged into `main`.
-- [ ] User-visible verification: from the dashboard, type a prefill, answer a subset of task-lane questions, click *Send N of M Responses* — AI follow-up renders.
+## Recommended next moves
 
-**Assumptions:**
-- Rebasing onto post-#150 main pulls in the workflow fixes (no host-port mapping for postgres, no upload-artifact step), so the prior CI failures on this PR are resolved structurally.
-- The new e2e regression spec (`frontend/e2e/assistant-chat-prefill.spec.ts`) doesn't depend on Anthropic — it uses `page.route` to stub `/ai-sessions/*/chat` deterministically, so it should be CI-stable.
-
-**Out of scope (deferred to TODO):**
-- Hardening the `currentChatRef.current !== sentForChatId` silent-return pattern across `handleSend`, `handleTaskSubmit`, `selectChat`, `refreshFacts`, `refreshActiveFix`, `refreshPreview`. PR #153 fixes the specific symptom; the broader audit is its own task in `TODO.md`.
-- Promoting `CI / e2e (pull_request)` to required on `main`. Holding off until two consecutive green PR runs (PR #150 was one; PR #153's run will be the second if it passes).
+1. **Promote `CI / e2e (pull_request)` to required on `main`.** Two consecutive PR runs (#150 and #153) have now finished green on the e2e job. That was the threshold the prior CI-recovery task set for promoting it. Branch protection update only — no code change.
+2. **Pick a backlog item.** Top of `TODO.md` "Up next" is the `data-testid` e2e-stability work (PR #152 spent five one-line selector updates chasing UI churn — adding stable test IDs to a small set of high-value elements would make those tests immune to copy/route renames). The new `currentChatRef` silent-return audit added in #153's session is in Backlog and is a natural pairing with the bug fix that was just shipped.
 
 ## Previous task — closed out
 
-**Task:** Land consolidated CI-recovery PR #150 and lock reliable CI gates on `main`.
+**Task:** Land PR #153 — fix the `AssistantChatPage` prefill `currentChatRef` bug that silently dropped AI follow-up responses in the task lane.
 
 **Status:** complete (2026-04-26).
 
-- PR #150 merged as commit `87bb20b` on `main`. Backend, frontend, and e2e all green on the merge SHA.
-- `CI / backend (pull_request)` added to required status checks on `main` (alongside the pre-existing `CI / frontend (pull_request)` requirement).
-- `CI / e2e (pull_request)` left as not-required pending one more green PR run.
+- PR #153 merged as commit `68fcdc6` on `main`. Backend, frontend, and e2e all green on the merged SHA after the env-var fix.
+- E2e CI needed a stub `ANTHROPIC_API_KEY` in the workflow so the AI-gated `POST /api/v1/ai-sessions` endpoint stops returning 503; the Playwright `page.route` stub still intercepts the actual `/chat` call in the browser, so no real Anthropic traffic occurs.
+- Regression test `frontend/e2e/assistant-chat-prefill.spec.ts` is part of the e2e suite going forward.