docs(ai): handoff state after magic-moment screen lands

Marks the magic-moment handoff-context screen as shipped, points the
next session at visual QA + push + draft PR, and captures the deferred
follow-ups (suggested-step chips, snapshot expansion, toolbar button
on revisits, owner analytics, Playwright e2e).

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

.ai/SESSION_LOG.md

@@ -12,6 +12,16 @@
 
 ---
 
+## 2026-04-27 21:30 EDT — Claude Code — Escalation Mode: magic-moment handoff-context screen on pickup
+
+- Continued the same session that shipped the live-arrival SSE subscription. Added the magic-moment screen on top.
+- New `frontend/src/components/flowpilot/HandoffContextScreen.tsx`: presentational 4-section view (header with problem summary + domain + step count + escalated-time + priority badge; "What's been tried" with engineer notes + step-count affordance; "AI assessment" with likely_cause / suggested_steps / confidence badge; "Start here" CTA). Confidence badge accepts both numeric (0..1) and string ("low"/"medium"/"high") shapes — backend emits the latter, the frontend type says `number`, runtime handles both. Renders an explicit "assessment unavailable — model didn't respond in time" branch when `ai_assessment_data` is null (the 5s timeout from `9bdd995` fired). `prefers-reduced-motion` swaps `animate-slide-up` for `animate-fade-in`. ARIA `role=dialog` + `aria-modal=true` + focus on primary CTA on mount + Esc dismiss when used as a re-openable overlay.
+- Integration in `frontend/src/pages/FlowPilotSessionPage.tsx`: on `/pilot/:id?pickup=true`, fetch the handoff list via `handoffsApi.listHandoffs` (account-scoped via RLS, no claim required) and find the latest unclaimed escalate handoff. If found, render the screen and skip `loadSession` (the senior would 404 pre-claim because they aren't yet `escalated_to_id`). "Start here" calls `handoffsApi.claimHandoff`, drops the `?pickup=true` query, and dismisses the screen — the existing `loadSession` effect then fires because the senior is now `escalated_to_id`. New "Context" toolbar button on active sessions (visible only when the senior arrived via the magic-moment flow this session — handoff lookup on demand) re-opens the screen as a dismissible overlay.
+- Verified end-to-end against the running dev stack: `listHandoffs` returns the unclaimed handoff with full payload (engineer_notes, snapshot keys); `claimHandoff` flips session status from `escalated` → `active` and sets `escalated_to_id`; subsequent `GET /ai-sessions/{id}` succeeds. `tsc -b` exit 0. No backend changes; backend tests still `32 passed in 18.91s`.
+- Deferred to TODOs in `CURRENT_TASK.md`: suggested-step chips below the chat input (Codex correction; threads through to `FlowPilotMessageBar`); `HandoffManager._generate_snapshot` expansion to include the recent diagnostic timeline pre-claim (today's snapshot is just `problem_summary, problem_domain, status, step_count, confidence_tier`); toolbar "Context" button visibility on revisited active sessions; owner-facing `/analytics/escalations` page; Playwright e2e for the GTM Loom demo path.
+- Branch state: 3 new commits (`b8627f4` SSE subscription, `f65b657` handoff doc bump, `8e9d22e` magic-moment screen). Branch is unpushed — next session pushes + opens draft PR.
+- Files touched this slice: `frontend/src/components/flowpilot/HandoffContextScreen.tsx` (new), `frontend/src/components/flowpilot/index.ts`, `frontend/src/pages/FlowPilotSessionPage.tsx`, `.ai/CURRENT_TASK.md`, `.ai/HANDOFF.md`, `.ai/SESSION_LOG.md`.
+
 ## 2026-04-27 21:00 EDT — Claude Code — Escalation Mode: frontend SSE subscription in EscalationQueue
 
 - Picked up `feat/escalation-metric-endpoint` after the Codex test-stabilization pass. Confirmed green starting state: focused backend subset `32 passed in 18.78s` with `-n auto`.