commerce: provider-neutral payment-request envelope (8 tests) — Phase 5 ext

payment.sx — payment-request materialises {:order :amount :currency :return-url}
at the IO edge (amount from the ledger, currency/return-url host-supplied), so
lib/commerce stays vendor-agnostic; SumUp/Stripe adapters live in the orders
service and order-settle!(ref, amount) is the resume seam. pending-payments
enumerates suspended orders + envelopes (host poller seam). Gotcha handled: a
Scheme string flow-payload round-trips back wrapped as {:scm-string ...} —
unwrapped via scm->string. Total 209/209 across 13 suites.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/commerce/tests/order.sx

@@ -65,3 +65,10 @@
 (commerce-test "post-restart-status" (order-status b "O3") :fulfilled)
 (commerce-test "post-restart-recon-ok" (order-recon b "O3") :ok)
 (commerce-test "post-restart-flow-done" (order-flow-status env id3) "done")
+
+;; --- payment-request envelope (provider-neutral) for the still-suspended O2 ---
+
+(commerce-test
+  "pending-payments-lists-suspended"
+  (pending-payments env b :GBP "https://shop/return")
+  (list {:id id2 :request {:order "O2" :amount 1200 :return-url "https://shop/return" :currency :GBP}}))