fix: overhaul PWA icons with v2 suffix to bust all cache layers

- Redesign favicon SVG with gradient border matching splash screen
- Rename all icon files with -v2 suffix to bypass browser/SW/PWA caches
- Delete 9 old/duplicate icon files (~13MB removed)
- Add nginx cache-control headers for icons and manifest
- Rename assets-cache to assets-cache-v2 to orphan stale SW cache
- Update all HTML, manifest, and component icon references

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

neode-ui/mock-backend.js

@@ -235,7 +235,7 @@ async function getDockerContainers() {
 
       const metadata = appMetadata[appId] || {
         title: appId,
-        icon: '/assets/img/favico.png',
+        icon: '/assets/icon/pwa-192x192-v2.png',
         description: `${appId} application`
       }
 
@@ -342,15 +342,15 @@ async function installPackage(id, manifestUrl) {
         title: 'Amin',
         shortDesc: 'Administrative interface for Archipelago',
         longDesc: 'Amin provides administrative tools and monitoring.',
-        icon: '/assets/img/favico.png'
+        icon: '/assets/icon/pwa-192x192-v2.png'
       }
     }
-    
+
     const metadata = packageMetadata[id] || {
       title: id.charAt(0).toUpperCase() + id.slice(1),
       shortDesc: `${id} application`,
       longDesc: `${id} application for Archipelago`,
-      icon: '/assets/img/favico.png'
+      icon: '/assets/icon/pwa-192x192-v2.png'
     }
     
     // Determine port