shared: opt-in CIP-33 reference-scripts for script-spending txs

When ESCROW_REF_UTXO / ADVERT_REF_UTXO env vars are set (format
<txhash>#<idx>), Claim/Submit/Accept/Reclaim/RetireAdvert call
.readFrom([refUtxo]) instead of inlining the validator CBOR via
.attach.SpendingValidator(). Lucid-evolution 0.4.30 auto-extracts
utxo.scriptRef into the script-witness map (dist/index.js:1903–1913),
so no separate attach call is needed. Default (env unset) is unchanged.

Adds buildLiveTxForPublishReferenceScripts (a one-shot tx that
publishes both validators as scriptRef-bearing UTxOs at a caller-
supplied address — typically the all-zero-pkh enterprise burn address)
and the supplier tx:publish-reference-scripts CLI that wraps it.

Targeted at testnet trial; mainnet rollout is a separate flip after
verification.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

supplier/.env.example

@@ -96,3 +96,19 @@ ADVERT_DETAIL_URI=
 # If empty, defaults to sha256("") =
 # e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
 ADVERT_DETAIL_HASH=
+
+# ─── Optional: CIP-33 reference scripts ───────────────────────────────────
+# Saves witness-set fee on script-spending txs (Claim, Submit, Accept,
+# Reclaim, RetireAdvert) by referencing on-chain script UTxOs instead of
+# inlining the full validator CBOR. Leave unset to use inlined scripts
+# (current behavior).
+#
+# Publish the two reference UTxOs (one-shot; uses SUPPLIER_PRIV_KEY_HEX +
+# OGMIOS_URL + NETWORK_ID from this env file):
+#   docker compose -f deploy/testnet/docker-compose.supplier.yml run --rm \
+#     --entrypoint sh supplier \
+#     -c "node_modules/.bin/tsx supplier/src/cli/publish-reference-scripts.ts"
+# Paste the two printed refs here AND into buyer/.env, then
+# `docker compose down && up -d` to apply.
+# ESCROW_REF_UTXO=<txhash>#0
+# ADVERT_REF_UTXO=<txhash>#1