docs(handoff): record answer-label fix (9c34d1e) + smoke-test note

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.ai/HANDOFF.md

@@ -2,7 +2,7 @@
 
 # HANDOFF.md
 
-**Last updated:** 2026-06-09
+**Last updated:** 2026-06-11
 
 **Active task:** L1 AI Tree Builder **Phase 2A — review findings RESOLVED, ready to re-push**.
 Branch `feat/l1-ai-tree-builder-phase-2a` (off `main` @ `87236b5`), **PR #193**:
@@ -17,7 +17,17 @@ Two architecture decisions logged in `.ai/DECISIONS.md` (2026-06-09): real
 `category`/`problem_text`/`pending_node` columns replacing the `meta` walked_path
 convention; ad-hoc walk restored.
 
-Next: commit + push the branch, let Gitea CI run, then merge PR #193. After merge:
+**2026-06-11 addition (commit `9c34d1e`, unpushed):** live-walk defect found by the user —
+the builder produced alternatives questions ("Microsoft account or local account?") while
+the UI only offered Yes/No. Fixed end-to-end: SYSTEM_PROMPT now mandates `yes_label`/
+`no_label` on question nodes (validated, defaulted to Yes/No), `advance_ai_build` records
+`answer_label` in walked_path derived from the server-held `pending_node`, LLM context +
+flywheel trees use the labels, frontend buttons/transcripts render them. Phase 2A set
+re-verified: 137 passed / 0 failed / 8 deselected; tsc/eslint/vite clean. Note: the live
+AI-quality smoke (spec §5.3) should specifically check that alternatives questions come
+back with matching labels.
+
+Next: push the branch, let Gitea CI run, then merge PR #193. After merge:
 prod `alembic upgrade head` — now **4 migrations**, new head **`61dda4f615c6`** (adds the
 three l1_walk_sessions columns + flips `flow_proposals.l1_session_id` FK to CASCADE + an
 escalations partial index). Then the live AI-quality smoke test before wide enablement