Editing a catalog amount now propagates beyond MongoDB. Stripe Prices are
immutable, so each changed currency mints a fresh Stripe Price at the new
amount, overwrites the cached stripePriceIds[currency] (which also fixes the
stale-price bug for new subscriptions), and repoints every live subscription
on that (row, currency) onto it with proration_behavior 'none' — the new
amount takes effect at the customer's next billing cycle, no mid-cycle charge.
The per-seat snapshot is refreshed so MRR reflects the go-forward rate.
Before committing the edit, the operator sees a warning with the affected
customer count, driven by a new GET /prices/:id/impact endpoint. Per-sub
failures are logged, never fatal; Stripe-disabled rows still re-snapshot.