Redeem Promo

Redeem a promo code on a FRESH org — no Checkout, no card (BACKE-2854).

Ethan directive 2026-07-22: a promo code must let the user continue without entering a CC. This creates the subscription server-side with the coupon attached (the self-serve twin of the manual comp flow), stamps metadata.organization_id so the subscription webhook grants tier + POC cap, and sets the org's plan fields inline so the user continues IMMEDIATELY (no webhook-latency paywall).

Only codes whose window bills $0 (percent_off=100 — every POC code by validated shape) can start service card-less: a partial discount with no payment method would generate a FAILING first invoice (service cut + dunning — strictly worse than the card form; the uncollectable shape POC-PROMO-CAP-2026-07-17 exists to prevent). Partial codes get a clear redirect to checkout, where the discount still applies. Card-ask happens at coupon end (finances' T-7d lifecycle).

Every failure carries a reason — never a silent no-op.