input+lnwallet: update taproot scripts to accept optional aux leaf

In this commit, we update all the taproot scripts to also accept an
optional aux leaf. This aux leaf can be used to add more redemption
paths for advanced channels, or just as an extra commitment space.

watchtower/wtclient/backup_task_internal_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
@@ -136,6 +137,7 @@ func genTaskTest(
 		if chanType.IsTaproot() {
 			scriptTree, _ := input.NewLocalCommitScriptTree(
 				csvDelay, toLocalPK, revPK,
+				fn.None[txscript.TapLeaf](),
 			)
 
 			pkScript, _ := input.PayToTaprootScript(
@@ -189,7 +191,7 @@ func genTaskTest(
 
 		if chanType.IsTaproot() {
 			scriptTree, _ := input.NewRemoteCommitScriptTree(
-				toRemotePK,
+				toRemotePK, fn.None[txscript.TapLeaf](),
 			)
 
 			pkScript, _ := input.PayToTaprootScript(

watchtower/wtclient/client_test.go

@@ -19,6 +19,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/channelnotifier"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/kvdb"
@@ -230,12 +231,14 @@ func (c *mockChannel) createRemoteCommitTx(t *testing.T) {
 
 	// Construct the to-local witness script.
 	toLocalScriptTree, err := input.NewLocalCommitScriptTree(
-		c.csvDelay, c.toLocalPK, c.revPK,
+		c.csvDelay, c.toLocalPK, c.revPK, fn.None[txscript.TapLeaf](),
 	)
 	require.NoError(t, err, "unable to create to-local script")
 
 	// Construct the to-remote witness script.
-	toRemoteScriptTree, err := input.NewRemoteCommitScriptTree(c.toRemotePK)
+	toRemoteScriptTree, err := input.NewRemoteCommitScriptTree(
+		c.toRemotePK, fn.None[txscript.TapLeaf](),
+	)
 	require.NoError(t, err, "unable to create to-remote script")
 
 	// Compute the to-local witness script hash.