refactor(10-12): migrate cloud/settings/UI SVGs to AppIcon

- SearchableModelSelect: chevronDown + pencilEdit
- SettingsCloudTab: warning (x2) + cloud icons
- CloudProviderTreeItem: cloud icon
- CloudFolderTreeItem: folder + fileDoc icons

frontend/src/components/cloud/CloudProviderTreeItem.vue

@@ -6,10 +6,7 @@
     @select="navigateToRoot"
   >
     <template #icon>
-      <svg class="w-4 h-4 shrink-0" :class="providerIconColor" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2"
-          d="M3 15a4 4 0 004 4h9a5 5 0 10-.1-9.999 5.002 5.002 0 10-9.78 2.096A4.001 4.001 0 003 15z" />
-      </svg>
+      <AppIcon name="cloud" class="w-4 h-4 shrink-0" :class="providerIconColor" />
     </template>
     <template #children="{ children }">
       <CloudFolderTreeItem
@@ -27,6 +24,7 @@
 import { computed } from 'vue'
 import { useRouter } from 'vue-router'
 import * as api from '../../api/client.js'
+import AppIcon from '../ui/AppIcon.vue'
 import TreeItem from '../ui/TreeItem.vue'
 import CloudFolderTreeItem from './CloudFolderTreeItem.vue'
 import { providerColor } from '../../utils/formatters.js'