Allow Vue nodes to have their colors changed from selection toolbox (#5720)

## Summary

Fixes https://github.com/Comfy-Org/ComfyUI_frontend/issues/5680 by
allowing Vue nodes to properly synchronize color changes with LiteGraph
nodes, implementing header darkening and light theme adjustments.

<img width="2496" height="1512" alt="Screenshot from 2025-09-21
20-00-36"
src="https://github.com/user-attachments/assets/e3bdf645-1e0b-4d11-9ae5-9401f43e8e96"
/>

## Changes

- **What**: Implemented color property synchronization between LiteGraph
and Vue node rendering systems
- **Core Fix**: Added `nodeData.color` and `nodeData.bgcolor` to [v-memo
dependencies](https://vuejs.org/api/built-in-directives.html#v-memo) to
trigger re-renders on color changes
- **Color Logic**: Added header darkening using [memoized color
adjustments](https://github.com/Comfy-Org/ComfyUI_frontend/blob/main/src/utils/colorUtil.ts)
to match LiteGraph's ColorOption system
- **Event System**: Enhanced property change instrumentation in
LGraphNode.setColorOption to emit color/bgcolor events

## Review Focus

Vue component reactivity timing - the v-memo fix was critical for
immediate color updates. Verify light theme color adjustments match the
drawNode monkey patch behavior in app.ts.

## Technical Details

```mermaid
graph TD
    A[User Sets Color] --> B[LGraphNode.setColorOption]
    B --> C[Sets node.color & node.bgcolor]
    C --> D[Triggers property:changed events]
    D --> E[Vue Node Manager Updates]
    E --> F[v-memo Detects Change]
    F --> G[NodeHeader Re-renders]
    G --> H[Header Darkening Applied]

    style A fill:#f9f9f9,stroke:#333,color:#000
    style H fill:#f9f9f9,stroke:#333,color:#000
```

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5720-Allow-Vue-nodes-to-have-their-colors-changed-from-selection-toolbox-2766d73d36508123b441d126a74a54b2)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Myestery <Myestery@users.noreply.github.com>
Co-authored-by: DrJKL <DrJKL@users.noreply.github.com>
Co-authored-by: github-actions <github-actions@github.com>

src/renderer/extensions/vueNodes/components/NodeHeader.vue

@@ -4,7 +4,8 @@
   </div>
   <div
     v-else
-    class="lg-node-header p-4 rounded-t-2xl cursor-move"
+    class="lg-node-header p-4 rounded-t-2xl w-full cursor-move"
+    :style="headerStyle"
     :data-testid="`node-header-${nodeData?.id || ''}`"
     @dblclick="handleDoubleClick"
   >
@@ -71,8 +72,11 @@ import EditableText from '@/components/common/EditableText.vue'
 import type { VueNodeData } from '@/composables/graph/useGraphNodeManager'
 import { useErrorHandling } from '@/composables/useErrorHandling'
 import { st } from '@/i18n'
+import { useSettingStore } from '@/platform/settings/settingStore'
 import { useNodeTooltips } from '@/renderer/extensions/vueNodes/composables/useNodeTooltips'
+import { applyLightThemeColor } from '@/renderer/extensions/vueNodes/utils/nodeStyleUtils'
 import { app } from '@/scripts/app'
+import { useColorPaletteStore } from '@/stores/workspace/colorPaletteStore'
 import { normalizeI18nKey } from '@/utils/formatUtil'
 import {
   getLocatorIdFromNodeData,
@@ -123,6 +127,23 @@ const tooltipConfig = computed(() => {
   return createTooltipConfig(description)
 })
 
+const headerStyle = computed(() => {
+  const colorPaletteStore = useColorPaletteStore()
+
+  const opacity = useSettingStore().get('Comfy.Node.Opacity') ?? 1
+
+  if (!nodeData?.color) {
+    return { backgroundColor: '', opacity }
+  }
+
+  const headerColor = applyLightThemeColor(
+    nodeData.color,
+    Boolean(colorPaletteStore.completedActivePalette.light_theme)
+  )
+
+  return { backgroundColor: headerColor, opacity }
+})
+
 const resolveTitle = (info: VueNodeData | undefined) => {
   const title = (info?.title ?? '').trim()
   if (title.length > 0) return title