Developer-mode setting gates the dev console

GameSettings.DeveloperMode (default ON) + a toggle in the settings panel. WorldScene
only stands up the dev console (and, later, the dev spawner) when it is enabled, so
without dev mode the backtick key does nothing. GodCameraSystem''s console arg is now
nullable (no console when dev mode off). Localized settings.devmode ru/en. Build clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Mods/Core/Languages/en/ui.json

@@ -108,6 +108,7 @@
   "settings.resolution": "Resolution",
   "settings.volume": "Volume",
   "settings.uiscale": "UI scale",
+  "settings.devmode": "Developer mode",
   "settings.apply": "Apply",
   "settings.back": "Back",
   "pause.title": "Paused",