commerce: reconciliation queries + federated-catalog stub (32 tests) — Phase 4 done

recon.sx — reconciliation as relational queries over the ledger: per-order
summary tuples + recon-statuso/neto/mismatcho miniKanren relations, so
overpaid/underpaid/settled and "settled to net N" are backward run* queries.
Tests cover double-charge guard, partial refund, webhook replay.

federation.sx (out-of-scope stub) — a federated catalog is the union of each
instance's product facts, so the same relations query cross-instance
(instances-with-sku, sku-offers, cheapest-offer). In-process mock, no network.

Completes the commerce-on-sx roadmap (Phases 1-4). Total 185/185 across 11 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 ledger order)
+SUITES=(catalog cart price api promo stack quote ledger order recon federation)
 
 OUT_JSON="lib/commerce/scoreboard.json"
 OUT_MD="lib/commerce/scoreboard.md"
@@ -68,6 +68,8 @@ run_suite() {
 (load "lib/commerce/quote.sx")
 (load "lib/commerce/ledger.sx")
 (load "lib/commerce/order.sx")
+(load "lib/commerce/recon.sx")
+(load "lib/commerce/federation.sx")
 (epoch 2)
 (eval "(define ct-pass 0)")
 (eval "(define ct-fail 0)")