fix: prevent My Apps crash when installing apps + add filebrowser to demo

The My Apps page went blank after installing apps because pkg['static-files'].icon
was accessed without optional chaining on dynamically installed packages that lack
the static-files property.

- Make static-files optional in PackageDataEntry type
- Add defensive ?.icon access with fallback in Apps.vue and AppDetails.vue
- Add filebrowser to mock backend staticDevApps (enables Cloud page in demo)
- Expand portMappings and marketplaceMetadata for all marketplace apps
- installPackage now uses staticApp() format for consistent data shape

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

neode-ui/src/views/Apps.vue

@@ -62,8 +62,8 @@
 
         <div class="flex items-start gap-4">
           <img
-            :src="pkg['static-files'].icon"
-            :alt="pkg.manifest.title"
+            :src="pkg['static-files']?.icon || `/assets/img/app-icons/${id}.png`"
+            :alt="pkg.manifest?.title || String(id)"
             class="w-16 h-16 rounded-lg object-cover bg-white/10"
             @error="handleImageError"
           />
@@ -72,7 +72,7 @@
               {{ pkg.manifest.title }}
             </h3>
             <p class="text-sm text-white/70 mb-2 truncate">
-              {{ pkg.manifest.description.short }}
+              {{ pkg.manifest?.description?.short || '' }}
             </p>
             <div class="flex items-center gap-2">
               <span