lnutils: Add logging helper for byte slices

LogBytesPreview returns a slog attribute that shows a hex preview of the
given byte slice. The result is truncated for readability. The preview
length is fixed to avoid leaking full binary payloads in logs while
still allowing identification of the data.

Author: gijswijs

lnutils/log.go

@@ -50,3 +50,16 @@ func LogPubKey(key string, pubKey *btcec.PublicKey) slog.Attr {
 
 	return btclog.Hex6(key, pubKey.SerializeCompressed())
 }
+
+// LogBytesPreview returns a slog attribute that shows a hex preview
+// of the given byte slice. The result is truncated for readability.
+// The preview length is fixed to avoid leaking full binary payloads
+// in logs while still allowing identification of the data.
+func LogBytesPreview(key string, data []byte) slog.Attr {
+	// Handle nil slice gracefully.
+	if data == nil {
+		return btclog.Fmt(key, "<nil>")
+	}
+
+	return btclog.Hex6(key, data)
+}