Contracts: refund and restore transitions for PayPal refund auto-detect

[BitcoinErrorLog]

Commerce: vendor the PayPal refund and reversal-cancelled order edges

Summary

The marketplace service records verified PayPal refunds on the order by itself: BitcoinErrorLog/pubky-marketplace-service cursor/paypal-refund-ipn-95c1. This branch keeps the Shop's contract tables in step with it.

• src/libs/commerce/contracts/state-machines.json gains only the paypal_refund and paypal_reversal_cancelled transitions, copied verbatim from the service artifact at 4ba877cd:
  • order: paid | ready_for_pickup | shipped | delivered | completed | return_received | cancel_requested | cancelled | return_requested | return_approved → refunded_external, and back from refunded_external to each of those states;
  • return: requested | approved | received → refunded, and back.
• The orderTransitions and returnTransitions client tables mirror those edges. They have no runtime importers besides the contract tests, so no UI action changes.
• The hash pin in contracts.contract.test.ts moves to the patched file, with a comment that says what it contains.

The vendored file was already behind service main in ways unrelated to refunds: the offer converted state, accepted → converted/expired, offer.checkout, and the payment late_completion edges. A full re-vendor changes how offers parse, so it is left for a separate change.

Proof

PREPUSH OK 520ba15c6212afd2ef9ac1c4d69e89fe6b99f2d8 38

Before the client tables changed, state-machines.contract.test.ts failed on exactly the missing refund edges. Afterwards src/libs/commerce passes: 31 files, 575 tests. No .tsx changed, so there is no VRT scene.

Not in this branch

• Copy for the payment_reversal_cancelled notification. The Shop quarantines unknown notification types per row until it has copy.
• Display of paymentReversedAt, paymentReversalCancelledAt, gatewayRefundReviewAt, and gatewayRefundUnmatched. The order schema is .passthrough(), so these keys are harmless today.

Head: 520ba15c6212afd2ef9ac1c4d69e89fe6b99f2d8 on cursor/shop-refund-edges-95c1. Base: release/shop-v0.6.8.