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>

assets/locales/ja.json

@@ -344,7 +344,7 @@
   "sketch.make_selection": "選択を{linetype}にする",
   "ui.1_degree_of_freedom": "自由度 1",
   "ui.3d_mouse_speed": "3D マウス速度",
-  "ui.3d_mouse_windows": "3D マウス (Windows)",
+  "ui.3d_mouse_windows": "3D マウス",
   "ui.3d_sketch": "3D スケッチ",
   "ui.about": "SolidCraft について",
   "ui.activate": "アクティブ化",