feat_overnight_studies_summary_card: Overnight "Ran While You Were Away" Summary Card

[SoundMindsAI]

Why

• Problem: Phase 1 (feat_overnight_autopilot) made an overnight study chain reviewable from any study's detail page (GET /api/v1/studies/{id}/chain + AutoFollowupChainPanel). But it solved reviewability, not discoverability. When the operator wakes up and loads /studies, the list looks identical to the night before — studies sorted created_at DESC, with no callout that three of them ran automatically while they slept and a chain finished. The operator has to already know to click into some member of the chain.
• Outcome: A "ran while you were away" card surfaces at the top of /studies when at least one overnight chain has completed since the operator's last visit. Each completed chain is listed with its anchor name, chain length, best metric, cumulative lift, and a one-click "Review chain" link to the anchor's detail page. The card is dismissible ("Got it") and re-appears only when a new chain completes. The result: the operator's first glance at /studies answers "what finished while I was away?" without hunting.
• Non-goal: This feature does not change the chaining engine, does not add an outgoing webhook / email / push notification (a backlog alternative), and does not introduce auth or a server-side per-user visited-state model. It is a read-only discoverability layer on top of the already-shipped Phase 1 surfaces.

Status

• Stage: PLAN
• Priority: (see idea file)

Definition of done

Spec defines AC-1: Completed chain appears in the discovery endpoint, AC-2: Single-study (no follow-up) is excluded, AC-3: since filters by tail completion, AC-4: In-flight chain excluded, AC-5: Empty result is 200, not error, AC-6: Malformed since returns 422 envelope, AC-7: Card renders only when chains exist, AC-8: "Got it" dismiss hides the card, AC-9: First-visit bounded lookback, AC-10: Stop-reason phrase never shows a raw wire value, AC-11: Failed / no-metric chain renders a fallback, not a crash, AC-12: One row per chain regardless of which member matched. Each must pass before merge.

Artifacts

• Idea: docs/00_overview/planned_features/02_mvp2/feat_overnight_studies_summary_card/idea.md
• Feature spec: docs/00_overview/planned_features/02_mvp2/feat_overnight_studies_summary_card/feature_spec.md
• Implementation plan: docs/00_overview/planned_features/02_mvp2/feat_overnight_studies_summary_card/implementation_plan.md

How to execute

The folder has both feature_spec.md and implementation_plan.md — both cross-model reviewed. Ready to ship:

/impl-execute docs/00_overview/planned_features/02_mvp2/feat_overnight_studies_summary_card/implementation_plan.md --all

--all runs the full story sequence end-to-end with per-story verification gates, phase-gate cross-model reviews via GPT-5.5, test coverage audit, push, PR creation, CI watch, Gemini Code Assist adjudication, and final cross-model review. The PR is opened but NOT merged — you merge it manually after review.

Notes

This issue is part of the MVP2 backlog issue-coverage sweep (2026-06-02) — every active MVP2 folder should have a tracking issue so external contributors can discover the work without grep-ing the planned-features tree. If you pick this up, drop a comment so others don't duplicate; if you find the linked idea/spec stale, run /idea-preflight first to refresh it.