feat: add download button to audio preview player (#8628)

## Summary
- Adds a download icon button to the `AudioPreviewPlayer` widget for
PreviewAudio and SaveAudio nodes
- Reuses the existing `downloadFile` utility (same as video download)
- Button appears inline next to volume/options controls, matching the
player's existing UI style

## Test plan
- [x] Add a PreviewAudio or SaveAudio node, run a workflow that produces
audio output
- [x] Verify the download icon appears in the audio player controls
- [x] Click the download button and confirm the audio file downloads
correctly
- [x] Verify the button does not appear when no audio is loaded


https://github.com/user-attachments/assets/7fb2df16-82a6-40aa-a938-aed57032e30b

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8628-feat-add-download-button-to-audio-preview-player-2fe6d73d365081e3997fc45d3bb8cffc)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/renderer/extensions/vueNodes/widgets/components/audio/AudioPreviewPlayer.vue

@@ -16,11 +16,11 @@
       <!-- Left Actions -->
       <div class="relative flex shrink-0 items-center justify-start gap-2">
         <!-- Play/Pause Button -->
-        <div
-          role="button"
-          :tabindex="0"
+        <Button
+          variant="textonly"
+          size="unset"
           :aria-label="$t('g.playPause')"
-          class="flex size-6 cursor-pointer items-center justify-center rounded hover:bg-interface-menu-component-surface-hovered"
+          class="size-6 rounded"
           @click="togglePlayPause"
         >
           <i
@@ -28,7 +28,7 @@
             class="text-secondary icon-[lucide--play] size-4"
           />
           <i v-else class="text-secondary icon-[lucide--pause] size-4" />
-        </div>
+        </Button>
 
         <!-- Time Display -->
         <div class="text-sm font-normal text-nowrap text-base-foreground">
@@ -57,11 +57,11 @@
       <!-- Right Actions -->
       <div class="relative flex shrink-0 items-center justify-start gap-2">
         <!-- Volume Button -->
-        <div
-          role="button"
-          :tabindex="0"
+        <Button
+          variant="textonly"
+          size="unset"
           :aria-label="$t('g.volume')"
-          class="flex size-6 cursor-pointer items-center justify-center rounded hover:bg-interface-menu-component-surface-hovered"
+          class="size-6 rounded"
           @click="toggleMute"
         >
           <i
@@ -73,19 +73,32 @@
             class="text-secondary icon-[lucide--volume-1] size-4"
           />
           <i v-else class="text-secondary icon-[lucide--volume-x] size-4" />
-        </div>
+        </Button>
+
+        <!-- Download Button -->
+        <Button
+          v-if="modelValue"
+          size="icon-sm"
+          variant="textonly"
+          :aria-label="$t('g.downloadAudio')"
+          :title="$t('g.downloadAudio')"
+          class="size-6 hover:bg-interface-menu-component-surface-hovered"
+          @click="handleDownload"
+        >
+          <i class="text-secondary icon-[lucide--download] size-4" />
+        </Button>
 
         <!-- Options Button -->
-        <div
+        <Button
           v-if="showOptionsButton"
-          role="button"
-          :tabindex="0"
+          variant="textonly"
+          size="unset"
           :aria-label="$t('g.moreOptions')"
-          class="flex size-6 cursor-pointer items-center justify-center rounded hover:bg-interface-menu-component-surface-hovered"
+          class="size-6 rounded"
           @click="toggleOptionsMenu"
         >
           <i class="text-secondary icon-[lucide--more-vertical] size-4" />
-        </div>
+        </Button>
       </div>
 
       <!-- Options Menu -->
@@ -137,11 +150,16 @@ import { computed, ref, useTemplateRef } from 'vue'
 import { useI18n } from 'vue-i18n'
 import { whenever } from '@vueuse/core'
 
+import { useToast } from 'primevue/usetoast'
+
+import { downloadFile } from '@/base/common/downloadUtil'
+import Button from '@/components/ui/button/Button.vue'
 import { cn } from '@/utils/tailwindUtil'
 
 import { formatTime } from '../../utils/audioUtils'
 
 const { t } = useI18n()
+const toast = useToast()
 
 const props = withDefaults(
   defineProps<{
@@ -187,6 +205,20 @@ const togglePlayPause = () => {
   isPlaying.value = !isPlaying.value
 }
 
+const handleDownload = () => {
+  if (!modelValue.value) return
+  try {
+    downloadFile(modelValue.value)
+  } catch {
+    toast.add({
+      severity: 'error',
+      summary: t('g.error'),
+      detail: t('g.failedToDownloadFile'),
+      life: 3000
+    })
+  }
+}
+
 const toggleMute = () => {
   if (audioRef.value) {
     isMuted.value = !isMuted.value