[backport core/1.36] fix: restore mask editor compatibility with Impact-Pack plugin (#7800)

Backport of #7762 to `core/1.36`

Automatically created by backport workflow.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7800-backport-core-1-36-fix-restore-mask-editor-compatibility-with-Impact-Pack-plugin-2d96d73d365081429479ffcf2e2b5181)
by [Unito](https://www.unito.io)

Co-authored-by: Terry Jia <terryjia88@gmail.com>

src/composables/maskeditor/useMaskEditorLoader.ts

@@ -104,7 +104,8 @@ export function useMaskEditorLoader() {
       // If we have a widget filename, we should prioritize it over the node image
       // because the node image might be stale (e.g. from a previous save)
       // while the widget value reflects the current selection.
-      if (widgetFilename) {
+      // Skip internal reference formats (e.g. "$35-0" used by some plugins like Impact-Pack)
+      if (widgetFilename && !widgetFilename.startsWith('$')) {
         try {
           // Parse the widget value which might be in format "subfolder/filename [type]" or just "filename"
           let filename = widgetFilename

src/extensions/core/maskeditor.ts

@@ -1,7 +1,7 @@
 import _ from 'es-toolkit/compat'
 import type { LGraphNode } from '@/lib/litegraph/src/litegraph'
 
-import { app } from '@/scripts/app'
+import { app, ComfyApp } from '@/scripts/app'
 import { useMaskEditorStore } from '@/stores/maskEditorStore'
 import { useDialogStore } from '@/stores/dialogStore'
 import { useMaskEditor } from '@/composables/maskeditor/useMaskEditor'
@@ -20,6 +20,18 @@ function openMaskEditor(node: LGraphNode): void {
   useMaskEditor().openMaskEditor(node)
 }
 
+// Open mask editor from clipspace (for plugin compatibility)
+// This is called when ComfyApp.open_maskeditor() is invoked without arguments
+function openMaskEditorFromClipspace(): void {
+  const node = ComfyApp.clipspace_return_node as LGraphNode | null
+  if (!node) {
+    console.error('[MaskEditor] No clipspace_return_node found')
+    return
+  }
+
+  openMaskEditor(node)
+}
+
 // Check if the dialog is already opened
 function isOpened(): boolean {
   return useDialogStore().isDialogOpen('global-mask-editor')
@@ -78,7 +90,16 @@ app.registerExtension({
       label: 'Decrease Brush Size in MaskEditor',
       function: () => changeBrushSize((old) => _.clamp(old - 4, 1, 100))
     }
-  ]
+  ],
+  init() {
+    // Set up ComfyApp static methods for plugin compatibility (deprecated)
+    ComfyApp.open_maskeditor = openMaskEditorFromClipspace
+
+    console.warn(
+      '[MaskEditor] ComfyApp.open_maskeditor is deprecated. ' +
+        'Plugins should migrate to using the command system or direct node context menu integration.'
+    )
+  }
 })
 
 const changeBrushSize = async (sizeChanger: (oldSize: number) => number) => {