Review "IP address has changed" functionality

The "IP address has changed" functionality is dodgy. Worse, when `allow_reverse_proxy` is used, the `X-Forwarded-For` header is trusted implicitly without validation.

https://github.com/beefproject/beef/blob/943a6fd2266f2652e64885c499e8f8fb5735ac10/core/main/handlers/hookedbrowsers.rb#L93-L102

Here's an example someone provided, showing that the stored IP address contains two IP addresses separated by `,`.


It may also result in many "IP address has changed" events in load balanced environments. Although I'm not sure that this is avoidable.

Start with core/main/handlers/hookedbrowsers.rb lines 93-102 and trace the "IP address has changed" handling, especially the allow_reverse_proxy path and X-Forwarded-For input. Compare the reported comma-separated address and load-balanced behavior, then define validation and completion criteria before making a change.

Written by the indexing model from the issue text.