commerce: order ledger on persist + idempotent reconciliation (20 tests)

ledger.sx — each order is an append-only persist stream "order/<id>";
status/total/paid/recon are folds over events (ledger = source of truth).
order-pay / order-refund are idempotent via persist/append-once keyed on the
payment ref, so a replayed SumUp webhook records once. order-recon-of
classifies unpaid/ok/underpaid/overpaid on net vs total; ledger-mismatches
finds genuine paid != ordered across streams. minikanren+scheme/flow+persist
verified coexisting in one process. Total 132/132 across 8 suites.

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

lib/commerce/conformance.sh

@@ -17,7 +17,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(catalog cart price api promo stack quote)
+SUITES=(catalog cart price api promo stack quote ledger)
 
 OUT_JSON="lib/commerce/scoreboard.json"
 OUT_MD="lib/commerce/scoreboard.md"
@@ -43,6 +43,11 @@ run_suite() {
 (load "lib/minikanren/intarith.sx")
 (load "lib/minikanren/matche.sx")
 (load "lib/minikanren/defrel.sx")
+(load "lib/persist/event.sx")
+(load "lib/persist/backend.sx")
+(load "lib/persist/log.sx")
+(load "lib/persist/kv.sx")
+(load "lib/persist/idempotency.sx")
 (load "lib/commerce/catalog.sx")
 (load "lib/commerce/cart.sx")
 (load "lib/commerce/price.sx")
@@ -50,6 +55,7 @@ run_suite() {
 (load "lib/commerce/promo.sx")
 (load "lib/commerce/stack.sx")
 (load "lib/commerce/quote.sx")
+(load "lib/commerce/ledger.sx")
 (epoch 2)
 (eval "(define ct-pass 0)")
 (eval "(define ct-fail 0)")