Web app: 3D mouse navigation through the Gamepad API (#1473)

The web app reads a 3D mouse through the Gamepad API and drives the camera through navigation::device, so it follows each page's navigation capabilities (#1336).

Co-authored-by: CamWight <CamWight@users.noreply.github.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

crates/ui-egui/src/lib.rs

@@ -149,6 +149,7 @@ pub mod sketch_tools;
 pub mod smart_extrude;
 #[cfg(test)]
 mod smart_extrude_ui_tests;
+pub mod space_mouse;
 pub mod stand_up;
 #[cfg(test)]
 mod sweep_dialog_tests;