wxWidgets does not propagate mouse motion events from child controls to parent windows. The Linux/macOS GUI was binding the random-pool mouse handlers only to the dialog/page and its direct children, which left nested controls such as static-box contents and the wizard image as dead zones.
Add a reusable recursive child-window event binder and use it in the keyfile generator, random pool enrichment dialog, and volume creation wizard. The root windows keep their existing generated bindings, while descendants are bound explicitly, avoiding duplicate handling on the root while covering all nested controls.
This makes the entropy gauge and the random pool update consistently no matter where the pointer moves inside the affected windows.
Fixes#1656.