fix: created btc dust amount constant and renaming (#2327)

* renamed BtcDustOffset as BtcNonceMarkOffset and created constant BTCWithdrawalDustAmount

* added changelog entry

changelog.md

@@ -66,6 +66,7 @@
 * [2233](https://github.com/zeta-chain/node/pull/2233) - fix `IsSupported` flag not properly updated in zetaclient's context
 * [2243](https://github.com/zeta-chain/node/pull/2243) - fix incorrect bitcoin outbound height in the CCTX outbound parameter
 * [2256](https://github.com/zeta-chain/node/pull/2256) - fix rate limiter falsely included reverted non-withdraw cctxs
+* [2327](https://github.com/zeta-chain/node/pull/2327) - partially cherry picked the fix to Bitcoin outbound dust amount
 
 ### CI
 

pkg/chains/chains.go

@@ -265,7 +265,8 @@ var (
 	}
 )
 
-func BtcDustOffset() int64 {
+// BtcNonceMarkOffset is the offset satoshi amount to calculate the nonce mark output
+func BtcNonceMarkOffset() int64 {
 	return 2000
 }
 

pkg/chains/conversion.go

@@ -11,7 +11,7 @@ import (
 // A very special value to mark current nonce in UTXO
 func NonceMarkAmount(nonce uint64) int64 {
 	// #nosec G701 always in range
-	return int64(nonce) + BtcDustOffset() // +2000 to avoid being a dust rejection
+	return int64(nonce) + BtcNonceMarkOffset()
 }
 
 // HashToString convert hash bytes to string

pkg/constant/constant.go

@@ -10,4 +10,7 @@ const (
 
 	// CmdMigrateTssFunds is used for CCTX of type cmd to give the instruction to the TSS to transfer its funds on a new address
 	CmdMigrateTssFunds = "cmd_migrate_tss_funds"
+
+	// BTCWithdrawalDustAmount is the minimum satoshis that can be withdrawn from zEVM to avoid outbound dust output
+	BTCWithdrawalDustAmount = 1000
 )