Billing lifecycle emails.

Concept set — not yet in code. The 13 templates the billing lifecycle still needs, on the exact production v3.5 shell (email/platform/). Sample data uses real tier pricing (Pro $15/mo, Team $15/seat, 3-seat floor). Covers the self-serve dunning → pause → pay-up → reactivate arc, invoices/receipts/statements with refunds, credits, discounts and Stripe Tax lines, seat true-ups, and the nonprofit program. Once approved these move into relay-platform/src/relay/email_templates.py and get re-rendered into the platform gallery.

Trigger map — status → email

Trigger	Email	Status
invoice.upcoming (T-3)	invoice-upcoming — renewal preview w/ line items	concept
invoice.paid	payment-receipt — itemized receipt (discounts, credits, tax)	concept
invoice.payment_failed №1	payment-failed — first notice	shipped
invoice.payment_failed №2+	payment-retry — retry count + Pay now	concept
last retry exhausted (T-1)	payment-final-notice — pause warning	concept
stripe_status → unpaid	account-paused — free-contract fallback + reactivate	concept
invoice.paid while unpaid/past_due	payment-recovered — plan restored	concept
charge.refunded	refund-issued — amount, card, timeline	concept
credit / commitment applied	credit-applied — source + burn-down	concept
monthly close (1st)	statement-ready — charges, refunds, credits, tax	concept
seat true-up (post-402 confirm)	seat-trueup — proration + new total	concept
subscription.deleted	subscription-canceled — teardown + 180d win-back	concept
trial T-7 / T-1	trial-ending	shipped
trial lapsed	trial-expired	shipped
trial → paid	converted-paid	shipped
plan change up / down	plan-changed / plan-downgraded	shipped
EAP grace ending	eap-grace-ending	shipped
nonprofit application submitted	nonprofit-received — review timeline + verification	concept
nonprofit application approved	nonprofit-approved — standing discount attached	concept