Reusable inventory: 3D tool rack (notebook + phone)

A tool-driven inventory overlay — a three.js rack you cycle with ◀ ▶ and
open with USE. Registry-based (not tied to a level type) so new tools just
add a model + component. Reuses the phone's 3D model; notebook is a blocky
placeholder tool. Dev route /?inventory=1; drop <Inventory/> into the navbar
after the merges.

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

src/main.tsx

@@ -6,13 +6,16 @@ import './styles.css'
 
 // three.js is lazy-loaded so the board never pays for it up front.
 const PhonePreview = lazy(() => import('./phone').then(m => ({ default: m.PhonePreview })))
+const Inventory = lazy(() => import('./inventory').then(m => ({ default: m.Inventory })))
 
 // Routing: the bare root is the game's front door (splash + campaign); /level/:id,
-// /admin, and the legacy ?level= deep link open the board; ?phone=1 is the spike.
+// /admin, and the legacy ?level= deep link open the board; ?phone / ?inventory spikes.
 const path = window.location.pathname
 const search = new URLSearchParams(window.location.search)
 const isBoard = path.startsWith('/level/') || path === '/admin' || search.has('level')
 const root = search.has('phone')
   ? <Suspense fallback={null}><PhonePreview /></Suspense>
-  : isBoard ? <App /> : <Play />
+  : search.has('inventory')
+    ? <Suspense fallback={null}><Inventory /></Suspense>
+    : isBoard ? <App /> : <Play />
 createRoot(document.getElementById('root')!).render(<StrictMode>{root}</StrictMode>)