[refactor] Replace PrimeVue ProgressSpinner with Lucide loader icon (#9372)

## Summary
- Replace PrimeVue `ProgressSpinner` with Lucide `loader-circle` icon in
App.vue and WorkspaceAuthGate.vue
- Use white color for loading spinner for better visibility on dark
backgrounds
- Remove `primevue/progressspinner` imports and update related test

## Changes
- **App.vue**: Replace `ProgressSpinner` with
`icon-[lucide--loader-circle]`
- **WorkspaceAuthGate.vue**: Same replacement
- **WorkspaceAuthGate.test.ts**: Remove ProgressSpinner mock, use
`.animate-spin` selector

## Review Focus
- Visual consistency of white spinner on dark background during initial
load

<img width="1596" height="1189" alt="스크린샷 2026-03-04 오후 6 28 27"
src="https://github.com/user-attachments/assets/d703db74-4123-4328-912a-45ac45cf6eeb"
/>
<img width="1680" height="1304" alt="스크린샷 2026-03-04 오후 6 28 24"
src="https://github.com/user-attachments/assets/8026d10a-7e06-4f95-849c-bc891756823c"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9372-refactor-Replace-PrimeVue-ProgressSpinner-with-Lucide-loader-icon-3196d73d3650815bb1d1d4554f7f744e)
by [Unito](https://www.unito.io)

src/platform/assets/components/ActiveMediaAssetCard.vue

@@ -24,20 +24,14 @@
         class="absolute inset-0 flex items-center justify-center bg-modal-card-placeholder-background"
       >
         <!-- Spinner for queued/initialization states -->
-        <i
-          v-if="isQueued"
-          class="icon-[lucide--loader-circle] size-8 animate-spin text-muted-foreground"
-        />
+        <Loader v-if="isQueued" size="md" class="text-muted-foreground" />
         <!-- Error icon for failed state -->
         <i
           v-else-if="isFailed"
           class="icon-[lucide--circle-alert] size-8 text-red-500"
         />
         <!-- Spinner for running without preview -->
-        <i
-          v-else
-          class="icon-[lucide--loader-circle] size-8 animate-spin text-muted-foreground"
-        />
+        <Loader v-else size="md" class="text-muted-foreground" />
       </div>
       <!-- Cancel/Delete button overlay -->
       <Button
@@ -80,6 +74,7 @@
 import { computed, ref } from 'vue'
 import { useI18n } from 'vue-i18n'
 
+import Loader from '@/components/common/Loader.vue'
 import Button from '@/components/ui/button/Button.vue'
 import { useJobActions } from '@/composables/queue/useJobActions'
 import type { JobListItem } from '@/composables/queue/useJobList'

src/platform/assets/components/AssetExportProgressDialog.vue

@@ -2,6 +2,7 @@
 import { computed, ref } from 'vue'
 import { useI18n } from 'vue-i18n'
 
+import Loader from '@/components/common/Loader.vue'
 import HoneyToast from '@/components/honeyToast/HoneyToast.vue'
 import Button from '@/components/ui/button/Button.vue'
 import type { AssetExport } from '@/stores/assetExportStore'
@@ -146,9 +147,7 @@ function closeDialog() {
                 </Button>
               </template>
               <template v-else-if="job.status === 'running'">
-                <i
-                  class="icon-[lucide--loader-circle] size-4 animate-spin text-base-foreground"
-                />
+                <Loader size="sm" class="text-base-foreground" />
                 <span class="text-xs text-base-foreground">
                   {{ progressPercent(job) }}%
                 </span>

src/platform/assets/components/ModelImportProgressDialog.vue

@@ -4,6 +4,7 @@ import Popover from 'primevue/popover'
 import { computed, ref } from 'vue'
 import { useI18n } from 'vue-i18n'
 
+import Loader from '@/components/common/Loader.vue'
 import HoneyToast from '@/components/honeyToast/HoneyToast.vue'
 import ProgressToastItem from '@/components/toast/ProgressToastItem.vue'
 import Button from '@/components/ui/button/Button.vue'
@@ -175,9 +176,7 @@ function closeDialog() {
       >
         <div class="flex min-w-0 flex-1 items-center gap-2 text-sm">
           <template v-if="isInProgress">
-            <i
-              class="icon-[lucide--loader-circle] size-4 flex-shrink-0 animate-spin text-muted-foreground"
-            />
+            <Loader size="sm" class="flex-shrink-0 text-muted-foreground" />
             <span
               class="min-w-0 flex-1 truncate font-bold text-base-foreground"
             >

src/platform/assets/components/UploadModelFooter.vue

@@ -49,10 +49,7 @@
       :disabled="!canFetchMetadata || isFetchingMetadata"
       @click="emit('fetchMetadata')"
     >
-      <i
-        v-if="isFetchingMetadata"
-        class="icon-[lucide--loader-circle] animate-spin"
-      />
+      <Loader v-if="isFetchingMetadata" />
       <span>{{ $t('g.continue') }}</span>
     </Button>
     <Button
@@ -63,7 +60,7 @@
       :disabled="!canUploadModel || isUploading"
       @click="emit('upload')"
     >
-      <i v-if="isUploading" class="icon-[lucide--loader-circle] animate-spin" />
+      <Loader v-if="isUploading" />
       <span>{{ $t('assetBrowser.upload') }}</span>
     </Button>
     <template
@@ -109,6 +106,7 @@
 <script setup lang="ts">
 import { ref } from 'vue'
 
+import Loader from '@/components/common/Loader.vue'
 import Button from '@/components/ui/button/Button.vue'
 import VideoHelpDialog from '@/platform/assets/components/VideoHelpDialog.vue'