Clarify when ipRiskSnapshot is not populated

Add documentation explaining that the IP risk snapshot is not provided
for low-risk networks, and that a null value indicates either no signals
or low-risk signals for the network.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: horgh

src/Record/Traits.php

@@ -173,6 +173,11 @@ class Traits implements \JsonSerializable
      *                 network. If you need realtime IP risk scoring based on behavioral signals on
      *                 your own network, please use minFraud. This attribute is only available from
      *                 the GeoIP2 Insights web service.
+     *
+     *                 We do not provide an IP risk snapshot for low-risk networks. If this field
+     *                 is not populated, we either do not have signals for the network or the
+     *                 signals we have show that the network is low-risk. If you would like to get
+     *                 signals for low-risk networks, please use the minFraud web services.
      */
     public readonly ?float $ipRiskSnapshot;