staticaddr/loopin: fix autoloop unconfirmed expiry

Unconfirmed deposits do not have a running CSV timer, so autoloop selection
should not treat them as earliest expiring candidates. Reusing different expiry
math from loop-in selection can make dynamic programming prefer mempool deposits
in tie cases.

Reuse static loop-in expiry calculations for autoloop candidates, treat
unconfirmed deposits as not yet aging in selection tie-breaks, and add a
selector test for confirmed versus unconfirmed ties.

Author: hieblmi

staticaddr/loopin/autoloop_dp.go

@@ -246,8 +246,10 @@ func filterAutoloopCandidateDeposits(maxAmount btcutil.Amount,
 			continue
 		}
 
-		residualLife := candidateDeposit.ConfirmationHeight +
-			int64(csvExpiry) - int64(blockHeight)
+		residualLife := int64(blocksUntilDepositExpiry(
+			uint32(candidateDeposit.ConfirmationHeight),
+			blockHeight, csvExpiry,
+		))
 
 		eligibleDeposits = append(
 			eligibleDeposits, autoloopCandidateDeposit{

staticaddr/loopin/autoloop_dp_test.go

@@ -80,6 +80,28 @@ func TestSelectNoChangeDepositsWithMemoryBudget(t *testing.T) {
 	}
 }
 
+// TestSelectNoChangeDepositsPrefersConfirmedTie verifies unconfirmed deposits
+// are not treated as earlier-expiring than confirmed deposits. Their CSV timer
+// has not started yet, so a same-value confirmed deposit should win the expiry
+// tie-break.
+func TestSelectNoChangeDepositsPrefersConfirmedTie(t *testing.T) {
+	t.Parallel()
+
+	unconfirmed := makeDeposit(34, 0, 5_000, 0)
+	confirmed := makeDeposit(35, 0, 5_000, 200)
+
+	deposits, err := selectNoChangeDeposits(
+		5_000, 5_000, []*deposit.Deposit{
+			unconfirmed, confirmed,
+		}, 1_000, 100, nil,
+	)
+	require.NoError(t, err)
+	require.Equal(
+		t, []string{confirmed.OutPoint.String()},
+		depositOutpoints(deposits),
+	)
+}
+
 // TestAutoloopDPSizing verifies the bucket sizing math. These cases are easier
 // to understand directly than by inferring the step from a larger selector
 // behavior test.