funding/test: add test for inline channel_ready processing

diff --git a/funding/manager_test.go b/funding/manager_test.go
index fdd448d..f6da32d 100644
--- a/funding/manager_test.go
+++ b/funding/manager_test.go
@@ -3,6 +3,7 @@ package funding
 import (
 	"bytes"
 	"context"
+	"crypto/rand"
 	"encoding/hex"
 	"errors"
 	"fmt"
@@ -12,6 +13,7 @@ import (
 	"reflect"
 	"runtime"
 	"strings"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -5177,3 +5179,69 @@ func TestMapGossipError(t *testing.T) {
 		require.ErrorIs(t, got, sentinel)
 	})
 }
+
+// TestChannelReadyUnknownChannelID verifies that channel_ready messages
+// referencing ChannelIDs unknown to the funding manager are consumed without
+// stalling the coordinator. After a batch of such messages drains through,
+// the manager must still be able to process a legitimate channel-open flow.
+func TestChannelReadyUnknownChannelID(t *testing.T) {
+	t.Parallel()
+
+	// Count FindChannel invocations so we can wait for every message to
+	// actually reach the coordinator's handler (ProcessFundingMsg is
+	// buffered and returns before processing).
+	var findChannelCalls atomic.Uint64
+
+	alice, bob := setupFundingManagers(
+		t, func(cfg *Config) {
+			origFindChannel := cfg.FindChannel
+			cfg.FindChannel = func(
+				node *btcec.PublicKey,
+				chanID lnwire.ChannelID,
+			) (*channeldb.OpenChannel, error) {
+
+				findChannelCalls.Add(1)
+
+				return origFindChannel(node, chanID)
+			}
+		},
+	)
+	t.Cleanup(func() {
+		tearDownFundingManagers(t, alice, bob)
+	})
+
+	// Send a batch of channel_ready messages with random (unknown)
+	// ChannelIDs to Alice from Bob.
+	const numUnknownMessages = 100
+	for i := 0; i < numUnknownMessages; i++ {
+		var randomChanID lnwire.ChannelID
+		_, err := rand.Read(randomChanID[:])
+		require.NoError(t, err)
+
+		unknownMsg := &lnwire.ChannelReady{
+			ChanID:                 randomChanID,
+			NextPerCommitmentPoint: bobAddr.IdentityKey,
+		}
+		alice.fundingMgr.ProcessFundingMsg(unknownMsg, bob)
+	}
+
+	// Wait for every message to flow through the coordinator's handler.
+	err := wait.NoError(func() error {
+		calls := findChannelCalls.Load()
+		if calls < numUnknownMessages {
+			return fmt.Errorf("FindChannel called %d times, "+
+				"want %d", calls, numUnknownMessages)
+		}
+
+		return nil
+	}, time.Second*15)
+	require.NoError(t, err)
+
+	// Confirm the coordinator is still able to drive a real funding
+	// flow. If any of the earlier messages had wedged the coordinator,
+	// this call would hang.
+	updateChan := make(chan *lnrpc.OpenStatusUpdate)
+	openChannel(
+		t, alice, bob, 500000, 0, 1, updateChan, true, nil,
+	)
+}