Feature: option to turn off automatic tank model loading

Lets people on limited data stop the Tankopedia from downloading 3D models automatically.

- Added an Automatically load 3D models switch to the settings page, on by default
- When off, the tank page hero shows a Load 3D model button where the loading bar sits
- Held back every model download on the tank page until requested, including the dynamic armor switcher and the gun flexibility visualizer
- Wrapped the tank sandbox in its own suspense boundary so the loading bar shows real progress instead of the whole page waiting on the model
- Measured loading progress from when each loading bar appears so it always starts empty
- Added the English strings; other languages fall back until translated

Fixes #311

packages/website/src/hooks/useStableProgress.ts

@@ -3,11 +3,13 @@ import { useRef } from "react";
 
 export function useStableProgress() {
   const { loaded, total } = useProgress();
+  const baseline = useRef(loaded);
   const progress = useRef(0);
+  const pending = total - baseline.current;
 
   progress.current = Math.max(
     progress.current,
-    total === 0 ? 0 : (loaded / total) * 100
+    pending <= 0 ? 0 : ((loaded - baseline.current) / pending) * 100
   );
 
   return progress.current;