Restructure redeem script to reduce size of redirect & claim txs

Deduplicate the public key used in the claim path of the warning escrow
output redeem script, of the v5 protocol, reducing the size of the
redirect & claim txs by 8 vbytes (32 WUs) each. The claim public key
doubles up as the trader's 2-of-2 multisig public key, used for both the
regular escrow output of the deposit tx and the redirection spend path
of the warning escrow output, so it may be reused through some
manipulation of the bitcoin stack.

Also reverse the order of the buyer & seller pubKeys & signatures, so
that the buyer signature is always higher up in the stack, for
consistency with the deposit tx redeem script.

This leads to the following two warning escrow output redeem scripts,
structured slightly differently:

Buyer's warning escrow output redeem script:

  <buyerPubKey> OP_SWAP
  OP_IF
    2 <sellerPubKey> OP_ROT 2 OP_CHECKMULTISIG
  OP_ELSE
    <claimDelay> OP_CHECKSEQUENCEVERIFY OP_DROP OP_CHECKSIG
  OP_ENDIF

Seller's warning escrow output redeem script:

  <sellerPubKey> OP_SWAP
  OP_IF
    2 OP_SWAP <buyerPubKey> 2 OP_CHECKMULTISIG
  OP_ELSE
    <claimDelay> OP_CHECKSEQUENCEVERIFY OP_DROP OP_CHECKSIG
  OP_ENDIF

Author: stejbac

core/src/main/java/bisq/core/btc/wallet/RedirectionTransactionFactory.java

@@ -140,8 +140,8 @@ private static TransactionWitness redeemP2WSH(Script witnessScript,
                                                   TransactionSignature sellerSignature) {
         var witness = new TransactionWitness(5);
         witness.setPush(0, new byte[]{});
-        witness.setPush(1, buyerSignature.encodeToBitcoin());
-        witness.setPush(2, sellerSignature.encodeToBitcoin());
+        witness.setPush(1, sellerSignature.encodeToBitcoin());
+        witness.setPush(2, buyerSignature.encodeToBitcoin());
         witness.setPush(3, new byte[]{1});
         witness.setPush(4, witnessScript.getProgram());
         return witness;

core/src/main/java/bisq/core/btc/wallet/WarningTransactionFactory.java

@@ -137,21 +137,31 @@ public Transaction finalizeWarningTransaction(Transaction warningTx,
         return warningTx;
     }
 
-    // TODO: Should probably reverse order of pubKeys & signatures, for consistency with deposit tx redeem script.
     static Script createRedeemScript(boolean isBuyer, byte[] buyerPubKey, byte[] sellerPubKey, long claimDelay) {
-        var scriptBuilder = new ScriptBuilder();
-        scriptBuilder.op(OP_IF)
-                .number(2)
-                .data(buyerPubKey)
-                .data(sellerPubKey)
-                .number(2)
-                .op(OP_CHECKMULTISIG);
+        var scriptBuilder = new ScriptBuilder()
+                .data(isBuyer ? buyerPubKey : sellerPubKey)
+                .op(OP_SWAP);
+
+        if (isBuyer) {
+            scriptBuilder.op(OP_IF)
+                    .number(2)
+                    .data(sellerPubKey)
+                    .op(OP_ROT)
+                    .number(2)
+                    .op(OP_CHECKMULTISIG);
+        } else {
+            scriptBuilder.op(OP_IF)
+                    .number(2)
+                    .op(OP_SWAP)
+                    .data(buyerPubKey)
+                    .number(2)
+                    .op(OP_CHECKMULTISIG);
+        }
 
         scriptBuilder.op(OP_ELSE)
                 .number(claimDelay)
                 .op(OP_CHECKSEQUENCEVERIFY)
                 .op(OP_DROP)
-                .data(isBuyer ? buyerPubKey : sellerPubKey)
                 .op(OP_CHECKSIG);
 
         return scriptBuilder.op(OP_ENDIF)

core/src/main/java/bisq/core/trade/protocol/bisq_v5/model/StagedPayoutTxParameters.java

@@ -27,8 +27,8 @@ public class StagedPayoutTxParameters {
     public static final long REDIRECT_TX_FEE_BUMP_OUTPUT_VALUE = 2000;
 
     private static final long WARNING_TX_EXPECTED_WEIGHT = 720; // 125 direct tx bytes, 220 witness bytes
-    private static final long CLAIM_TX_EXPECTED_WEIGHT = 519;   //  82 direct tx bytes, 191 witness bytes
-    public static final long REDIRECT_TX_MIN_WEIGHT = 593;      //  82 direct tx bytes, 265 witness bytes
+    private static final long CLAIM_TX_EXPECTED_WEIGHT = 487;   //  82 direct tx bytes, 159 witness bytes
+    public static final long REDIRECT_TX_MIN_WEIGHT = 561;      //  82 direct tx bytes, 233 witness bytes
 
     // Min. fee rate for staged payout txs. If fee rate used at take offer time was higher we use that.
     // We prefer a rather high fee rate to not risk that the tx gets stuck if required fee rate would