feat: implement NodeLibrarySidebarTabV2 with Reka UI components (#8548)

## Summary

Implement a redesigned Node Library sidebar using Reka UI components
with virtualized tree rendering and improved UX.

## Changes

- **What**: 
  - Add three-tab structure (Essential, All, Custom) using Reka UI Tabs
- Implement TreeExplorerV2 with virtualized tree using
TreeRoot/TreeVirtualizer for performance
  - Add node hover preview with teleport to show NodePreview component
  - Implement context menu for toggling favorites on nodes
  - Add search functionality that auto-expands matching folders
- Create panel components: EssentialNodesPanel, AllNodesPanel,
CustomNodesPanel
  - Add 'Open Manager' button in CustomNodesPanel
  - Use custom icons: comfy--node for nodes, ph--folder-fill for folders
  - New node preview component: `NodePreviewCard`
  - Api node folder icon
  - Node drag preview

- **Feature Flag**: Enabled via URL parameter `?nodeRedesign=true`

## Review Focus

- TreeExplorerV2.vue uses `[...expandedKeys]` to prevent internal
mutation by Reka UI TreeRoot
- Context menu injection key is exported from TreeExplorerV2Node.vue and
imported by TreeExplorerV2.vue
- Hover preview uses teleport to
`#node-library-node-preview-container-v2`

## Screenshots (if applicable)

| Feature | Screenshot | 
|---|---|
| All nodes tab |<img width="323" height="761" alt="image"
src="https://github.com/user-attachments/assets/1976222b-83dc-4a1b-838a-2d49aedea3b8"
/>|
| Custom nodes tab | <img width="308" height="748" alt="image"
src="https://github.com/user-attachments/assets/2c23bffb-bdaa-4c6c-8cac-7610fb7f3fb7"
/>|
|Api nodes icon | <img width="299" height="523" alt="image"
src="https://github.com/user-attachments/assets/e9ca05b0-1143-44cf-b227-6462173c7cd0"
/>|
| node preview|<img width="499" height="544" alt="image"
src="https://github.com/user-attachments/assets/8961a7b4-77ae-4e57-99cf-62d9e4e17088"
/>|
| node drag preview | <img width="434" height="289" alt="image"
src="https://github.com/user-attachments/assets/b5838c90-65d4-4bee-b2b3-c41b57870da8"
/>|



Test by adding `?nodeRedesign=true` to the URL

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8548-WIP-feat-implement-NodeLibrarySidebarTabV2-with-Reka-UI-components-2fb6d73d36508134b7e0f75a2c9b976a)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: bymyself <cbyrne@comfy.org>

src/components/common/TextTickerMultiLine.vue

@@ -0,0 +1,66 @@
+<template>
+  <div>
+    <!-- Hidden single-line measurement element for overflow detection -->
+    <div
+      ref="measureRef"
+      class="invisible absolute inset-x-0 top-0 overflow-hidden whitespace-nowrap pointer-events-none"
+      aria-hidden="true"
+    >
+      <slot />
+    </div>
+
+    <MarqueeLine v-if="!secondLine">
+      <slot />
+    </MarqueeLine>
+
+    <div v-else class="flex flex-col w-full">
+      <MarqueeLine>{{ firstLine }}</MarqueeLine>
+      <MarqueeLine>{{ secondLine }}</MarqueeLine>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { useMutationObserver, useResizeObserver } from '@vueuse/core'
+import { ref } from 'vue'
+
+import MarqueeLine from './MarqueeLine.vue'
+import { splitTextAtWordBoundary } from '@/utils/textTickerUtils'
+
+const measureRef = ref<HTMLElement | null>(null)
+const firstLine = ref('')
+const secondLine = ref('')
+
+function splitLines() {
+  const el = measureRef.value
+  const text = el?.textContent?.trim()
+  if (!el || !text) {
+    firstLine.value = ''
+    secondLine.value = ''
+    return
+  }
+
+  const containerWidth = el.clientWidth
+  const textWidth = el.scrollWidth
+
+  if (textWidth <= containerWidth) {
+    firstLine.value = text
+    secondLine.value = ''
+    return
+  }
+
+  const [first, second] = splitTextAtWordBoundary(
+    text,
+    containerWidth / textWidth
+  )
+  firstLine.value = first
+  secondLine.value = second
+}
+
+useResizeObserver(measureRef, splitLines)
+useMutationObserver(measureRef, splitLines, {
+  childList: true,
+  characterData: true,
+  subtree: true
+})
+</script>