Fix help manual layout: shrink tabs to fit panel, space implant rows

- 10+ tabs at fixed 108px overflowed the 920px panel; tabs now shrink to fit
- Implant rows grew a rarity/cap sub-line but kept 20px spacing; now 26px
  with 10 rows per column (20 items/page, 5 pages for 82 items)
- Bump asset cache to v=39; smoke test asserts tabs stay on-screen

js/sprites.js

@@ -81,7 +81,7 @@ const Sprites = {
       const img = new Image();
       img.onload = () => { this.imgs[name] = img; if (--pending === 0) G.imagesLoaded = true; };
       img.onerror = () => { if (--pending === 0) G.imagesLoaded = true; };
-      img.src = 'assets/' + name + '.png?v=38';
+      img.src = 'assets/' + name + '.png?v=39';
     }
   },