kai-retentionlisted

## Objective A retention system the business can run: a churn diagnosis that names which churn type is actually costing money, an engagement health score with defined signals and thresholds, intervention playbooks per risk tier, a win-back sequence, involuntary-churn prevention, and a 90-day implementation roadmap with the metrics to watch. Diagnose before prescribing. A loyalty program aimed at voluntary churn does nothing when the real leak is failed payments, and a dunning sequence does nothing when customers leave in week three because onboarding never delivered value. ## Done when Work type `strategy-plan` — floor **E3/C3/O1** (`harness/eco-floors.yaml`). The system is a plan; nothing leaves the workspace until a human sends it. - **E3** — a named human approved the retention playbook, the engagement scoring spec, and the email sequences. - **C3** — `banned_word_check` clean on all customer-facing copy, every email sequence at **10+/16** on Four U's, and a non-author read the system end to end. Max 2 auto-retry cycles on gate failures for email content. - **O1** — the plan names its metric with baseline, threshold, window, and owner: monthly churn rate, cohort retention curve, health score distribution, NPS trend, and expansion versus contraction revenue. Sending any sequence is separate work under `email-lifecycle` (E5/C3/O3), where unsubscribe and sender-identity compliance is a C4 field-standard item, not a lint. ## Constraints - **Read `MARKETING.md` from the