Replace Create-rule header portraits with real PNGs so the circles paint.

The old SVG wrappers nested corrupt PNGs, so browsers fetched the files but showed empty rings.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/layout.tsx

@@ -123,19 +123,19 @@ export default function RootLayout({ children }: { children: ReactNode }) {
           rel="preload"
           as="image"
           href={getAssetPath(ASSETS.AVATAR_1)}
-          type="image/svg+xml"
+          type="image/png"
         />
         <link
           rel="preload"
           as="image"
           href={getAssetPath(ASSETS.AVATAR_2)}
-          type="image/svg+xml"
+          type="image/png"
         />
         <link
           rel="preload"
           as="image"
           href={getAssetPath(ASSETS.AVATAR_3)}
-          type="image/svg+xml"
+          type="image/png"
         />
       </head>
       <body