Fix PWA icon dimensions and remove duplicate

- Update icon-192x192.png to correct size 500x192 (was incorrectly declared as 192x192)
- Merge duplicate icon-512x512.png entries into single icon with 'any maskable' purpose
- Eliminates manifest warnings for icon size mismatches

nuxt4/nuxt.config.ts

@@ -37,7 +37,7 @@ export default defineNuxtConfig({
       icons: [
         {
           src: '/icon-192x192.png',
-          sizes: '192x192',
+          sizes: '500x192',
           type: 'image/png',
           purpose: 'any'
         },
@@ -45,13 +45,7 @@ export default defineNuxtConfig({
           src: '/icon-512x512.png',
           sizes: '512x512',
           type: 'image/png',
-          purpose: 'any'
-        },
-        {
-          src: '/icon-512x512.png',
-          sizes: '512x512',
-          type: 'image/png',
-          purpose: 'maskable'
+          purpose: 'any maskable'
         }
       ],
       screenshots: [