feat: add Inventory page — composites and layout sections

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/pages/Inventory/Inventory.tsx

@@ -1,6 +1,8 @@
 import { Link } from 'react-router-dom'
 import styles from './Inventory.module.css'
 import { PrimitivesSection } from './sections/PrimitivesSection'
+import { CompositesSection } from './sections/CompositesSection'
+import { LayoutSection } from './sections/LayoutSection'
 
 const NAV_ITEMS = [
   { label: 'Primitives', href: '#primitives' },
@@ -30,6 +32,8 @@ export function Inventory() {
 
         <main className={styles.content}>
           <PrimitivesSection />
+          <CompositesSection />
+          <LayoutSection />
         </main>
       </div>
     </div>