v0.16.0 — sheleg-dev

• stripe-billing/references/cancellation-and-retention.md gains A pause instead of a
  cancellation: the screen rule (the pause offer does not lengthen the cancel path; one
  screen, cancel one tap away), then Stripe's two pauses side by side. pause_collection
  (behavior keep_as_draft, mark_uncollectible or void; resumes_at) keeps status
active and access on, and reaches the app only as customer.subscription.updated. The
  Pause endpoint (flexible billing_mode, API 2026-09-30.endive) sets paused, stops
  invoices and emits customer.subscription.paused and .resumed.
  status_details.paused.subscription.type separates a requested pause from a trial that
  ended without a payment method (trial_settings.end_behavior.missing_payment_method) and
  from a payment-failure pause. Four test-matrix lines; every fact cites docs.stripe.com,
  read 2026-10-22.
• price-integrity.md cites docs.stripe.com/keys for the key prefixes assertStripeEnv
  reads. Board row B-86 is closed: its assertion and CREDENTIAL_BOUNDARIES row shipped in
  v0.13.4 and the row had stayed open.
• subscription-lifecycle.md: mapStatus maps paused to its own paused, no longer canceled;
  a paused subscription resumes. Board: B-107 (the client's API pin predates the Pause endpoint)
  and B-108 (billing_mode migration) filed.