[Epic]: V1→V2 parity — Online Payments #654

Domain epic under the V1→V2 feature-parity umbrella (#136). Full audit: 03-online-payments.md (2026-07-18 parity audit, v1 prep/v180 vs v2 develop).

Summary: No Stripe, no PayPal, no guest payment page, no shared callback pipeline — confirmed zero code (composer.json has no stripe/paypal package, Modules/Payments/routes/web.php is an empty stub) beyond a settings tab that persists gateway credentials nobody reads.

Sub-issues

• [Payments]: Guest online-payment page & shared gateway pipeline #653 — Guest online-payment page & shared gateway pipeline — foundation, blocks the other two
• [Payments]: Stripe Checkout Sessions gateway — create session, callback, record payment #651 — Stripe Checkout Sessions gateway
• [Payments]: PayPal Orders v2 gateway — create order, capture, record payment #652 — PayPal Orders v2 gateway
• [Payments]: Online Payments Journal #144 — Online Payments Journal (GatewayTransaction logging)
• [Feature Request]: PayPal Complete Payments - Venmo and Advanced Credit Cards #517 — PayPal Venmo + Advanced Credit Cards (improved — depends on [Payments]: PayPal Orders v2 gateway — create order, capture, record payment #652)

Specific

Reach online-payment feature parity with v1: an anonymous "pay this invoice" page offering enabled gateways, working Stripe and PayPal integrations with idempotent payment recording, and a transaction journal for every attempt.

Measurable

All 5 sub-issues closed; a customer can open a share-link invoice, pay via Stripe or PayPal, and see the invoice marked paid with a journal entry recorded.

Achievable

#653 (shared pipeline + guest page) is the dependency both gateways build on; #144 (journal) is used by all three; #517 extends #652 once it exists.

Relevant

Online payment collection is core cash-flow functionality; v1 users relying on Stripe/PayPal today have zero equivalent in v2.

Time-Bound

Shared pipeline: 1 sprint. Both gateways: 1 sprint after. #517: immediately following PayPal.