lnwallet: add field CommitTxBlockHeight to ResolutionReq

Introduce `CommitTxBlockHeight` field to the `ResolutionReq` structure
and related methods. This field records the block height where a
commitment transaction has confirmed.

Author: ffranr

contractcourt/chain_watcher.go

@@ -1061,7 +1061,8 @@ func (c *chainWatcher) dispatchLocalForceClose(
 		"detected", c.cfg.chanState.FundingOutpoint)
 
 	forceClose, err := lnwallet.NewLocalForceCloseSummary(
-		c.cfg.chanState, c.cfg.signer, commitSpend.SpendingTx, stateNum,
+		c.cfg.chanState, c.cfg.signer, commitSpend.SpendingTx,
+		uint32(commitSpend.SpendingHeight), stateNum,
 		c.cfg.auxLeafStore, c.cfg.auxResolver,
 	)
 	if err != nil {

lnwallet/aux_resolutions.go

@@ -77,6 +77,10 @@ type ResolutionReq struct {
 	// CommitTx is the force close commitment transaction.
 	CommitTx *wire.MsgTx
 
+	// CommitTxBlockHeight is the block height where the commitment
+	// transaction confirmed. It is 0 if unknown or not confirmed yet.
+	CommitTxBlockHeight uint32
+
 	// CommitFee is the fee that was paid for the commitment transaction.
 	CommitFee btcutil.Amount