3.1.1 — Webhook settles the right order on inline retries (#69)

Inline (popup) payments that the customer retried after closing the Paystack
window now confirm through the webhook, and charges for orders that can no
longer take them are recorded and acknowledged instead of retried for days.

Fixed

• Inline payments retried on the same cart now confirm via the webhook
  (#69). Closing the Paystack popup cancels the order and reuses its cart,
  so a retry left several orders on one quote, and the webhook — which
  required exactly one — left the paid order pending whenever it was the path
  that confirmed payment (customer closed the tab, verify call failed). Order
  lookup now lives in Model/WebhookOrderResolver: the reference as an
  increment id, then an order the reference is already bound to, then the
  order id the checkout now sends in the transaction metadata (matched with
  its quote), then the quote — a lone order as before, otherwise the single
  still-payable Paystack order, and never a guess among several.
• A charge for an order that can no longer take it is acknowledged once
  recorded, instead of retried for ~72 hours. Canceled, closed or complete
  orders, or orders with nothing left due, now return the new order_closed
  reason: the webhook answers 200 once a history comment asking the
  merchant to refund or reconcile the charge is saved on the order, and logs
  it at critical. Long runs of 503 are what make Paystack back off or
  disable an endpoint. Orders on hold or under payment review keep retrying.
• A rejected real charge is never acknowledged without a record. For any
  decided rejection where real money moved, the webhook now retries (503)
  until the order-history comment is saved, rather than answering 200 when
  that write failed.

Changed

• The inline checkout sends the placed order's id as metadata.orderId on
  the Paystack transaction.
• The inline REST verify endpoint and the Redirect callback report
  order_closed (terminal, same customer message as order_not_payable)
  for canceled/closed/complete or fully-paid orders.

Maintenance

• StorefrontPaystackCheckoutRendersTest (MFTF) no longer races Magento's
  shipping-estimate loading mask; it uses the core
  CheckoutSelectFlatRateShippingMethodActionGroup and
  StorefrontCheckoutClickNextButtonActionGroup.
• .env.sample, a leftover Docker template, is no longer included in the
  Marketplace package.

Known limitations

• Transactions without metadata.orderId (started before this release, or
  from checkouts that replace Magento's standard payment renderer, e.g. Hyvä
  or one-step checkouts) still resolve by quote: a late bank-transfer/USSD
  settlement for a cancelled attempt can bind to the live retry order on the
  same quote. The planned move to server-side transaction initialization
  removes client-supplied ids altogether.
• A quote with several orders of which none (or more than one) is payable
  still ends in "order not found" — now logged at error with the candidate
  orders, but without an order-history comment.