shared: bump publish-refs setMinFee floor 200K → 500K

Lucid's auto-fee calculation under-estimates the publish-refs tx by
~5K lovelace on Vector L2 mainnet (observed: required 372,658, lucid
computed 367,197 → ogmios rejected with code 3122 InsufficientFee).

Bumping the floor to 500K guarantees lucid pays enough. Cost: 0.13 AP3X
overhead, one-shot. Doesn't affect ongoing script-spending txs (those
have their own setMinFee already at 200K, unchanged).

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

packages/shared/src/tx/internal/publishReferenceScripts.ts

@@ -83,7 +83,11 @@ export async function buildLiveTxForPublishReferenceScripts(
         advertScript,
       )
       .addSignerKey(walletKey.pubKeyHash)
-      .setMinFee(200_000n);
+      // Bump floor to 500K — lucid's auto-fee under-estimates this tx by
+      // ~5K lovelace on Vector L2 mainnet (observed: needed 372,658, lucid
+      // computed 367,197). Publish is a one-shot, so 0.13 AP3X overhead is
+      // a fine price for not having to chase the fee model.
+      .setMinFee(500_000n);
 
     const completed = await txBuilder.complete({
       presetWalletInputs: realWalletUtxos,