feat: show loading spinner and uploading filename during image upload (#9189)

## Summary
- Show a canvas-based loading spinner on image upload nodes (LoadImage)
during file upload via drag-drop, paste, or file picker
- Display the uploading file's name immediately in the filename dropdown
instead of showing the previous file's name
- Show the uploading audio file's name immediately in the audio widget
during upload

## Changes
- **`useNodeImageUpload.ts`**: Add `isUploading` flag and
`onUploadStart` callback to the upload lifecycle; clear `node.imgs`
during upload to prevent stale previews
- **`useImagePreviewWidget.ts`**: Add `renderUploadSpinner` that draws
an animated arc spinner on the canvas when `node.isUploading` is true;
guard against empty `imgs` array
- **`useImageUploadWidget.ts`**: Set `fileComboWidget.value` to the new
filename on upload start; clear `node.imgs` on combo widget change
- **`uploadAudio.ts`**: Set `audioWidget.value` to the new filename on
upload start
- **`litegraph-augmentation.d.ts`**: Add `isUploading` property to
`LGraphNode`



https://github.com/user-attachments/assets/818ce529-cb83-428a-8c98-dd900a128343



## Test plan
- [x] Upload an image via file picker on LoadImage node — spinner shows
during upload, filename updates immediately
- [x] Drag-and-drop an image onto LoadImage node — same behavior
- [x] Paste an image onto LoadImage node — same behavior
- [x] Change the dropdown selection on LoadImage — old preview clears,
new image loads
- [x] Upload an audio file — filename updates immediately in the widget

🤖 Generated with [Claude Code](https://claude.com/claude-code)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9189-feat-show-loading-spinner-and-uploading-filename-during-image-upload-3126d73d365081e4af27cd7252f34298)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/composables/node/useNodeImageUpload.ts

@@ -1,6 +1,7 @@
 import { useNodeDragAndDrop } from '@/composables/node/useNodeDragAndDrop'
 import { useNodeFileInput } from '@/composables/node/useNodeFileInput'
 import { useNodePaste } from '@/composables/node/useNodePaste'
+import { t } from '@/i18n'
 import type { LGraphNode } from '@/lib/litegraph/src/litegraph'
 import { useToastStore } from '@/platform/updates/common/toastStore'
 import type { ResultItemType } from '@/schemas/apiSchema'
@@ -62,6 +63,8 @@ interface ImageUploadOptions {
    * @example 'input', 'output', 'temp'
    */
   folder?: ResultItemType
+  onUploadStart?: (files: File[]) => void
+  onUploadError?: () => void
 }
 
 /**
@@ -90,10 +93,29 @@ export const useNodeImageUpload = (
   }
 
   const handleUploadBatch = async (files: File[]) => {
-    const paths = await Promise.all(files.map(handleUpload))
-    const validPaths = paths.filter((p): p is string => !!p)
-    if (validPaths.length) onUploadComplete(validPaths)
-    return validPaths
+    if (node.isUploading) {
+      useToastStore().addAlert(t('g.uploadAlreadyInProgress'))
+      return []
+    }
+    node.isUploading = true
+
+    try {
+      node.imgs = undefined
+      node.graph?.setDirtyCanvas(true)
+      options.onUploadStart?.(files)
+
+      const paths = await Promise.all(files.map(handleUpload))
+      const validPaths = paths.filter((p): p is string => !!p)
+      if (validPaths.length) {
+        onUploadComplete(validPaths)
+      } else {
+        options.onUploadError?.()
+      }
+      return validPaths
+    } finally {
+      node.isUploading = false
+      node.graph?.setDirtyCanvas(true)
+    }
   }
 
   // Handle drag & drop