Add returns/RMA foundation hooks to Lunar v1.x

[tazzytazzy]

Preliminary release of adding to the hook surface needed to unblock reusable returns/RMA integrations in Lunar v1.x.

Let me know what you think. Probably few tweaks here and there might be needed to help align with your goals. Let me know and I'll work on it.

• add OrderPaid plus canonical refund orchestration via RefundTransaction
• add pre-refund authorization DTOs/contracts and refund lifecycle events
• expand PaymentRefund with refund transaction context and allocation passthrough
• add OrderLineCapabilitiesInterface with the default conservative resolver
• route admin refund actions through the orchestration path
• document the new refund and order hook surface in the Lunar docs

Test coverage:

• refund allowed, denied, driver-failed, and thrown-exception paths
• RefundRequested ordering before the driver call
• RefundCompleted and RefundFailed dispatch behavior
• allocation passthrough and refund transaction hydration
• default and override order-line capability behavior, including unplaced lines
• admin header and bulk refund flows
• OrderPaid coverage for Offline, Stripe, Opayo, and Paypal
• Paypal expanded PaymentRefund coverage

Verified with:

• vendor/bin/pint --dirty --format agent
• vendor/bin/pest tests/core/Unit/Actions/Orders/RefundTransactionTest.php tests/core/Unit/Base/OrderLineCapabilitiesTest.php tests/core/Unit/PaymentTypes/OfflinePaymentTypeTest.php tests/stripe/Unit/StripePaymentTypeTest.php tests/opayo/Feature/OpayoPaymentTypeTest.php tests/admin/Feature/Filament/Resources/OrderResource/Pages/ManageOrderTest.php tests/paypal/Unit/PaypalPaymentTypeTest.php

Result:

• 34 tests passed
• 207 assertions

[tazzytazzy]

I'm working on resolving these failures.