feat: add display name mappings for Essentials tab nodes (#9072)

## Summary

Add frontend-only display name mappings for nodes shown in the
Essentials tab, plus parse the new `essentials_category` field from the
backend.

## Changes

- **What**: Created `src/constants/essentialsDisplayNames.ts` with a
static mapping of node names to user-friendly display names (e.g.
`CLIPTextEncode` → "Text", `ImageScale` → "Resize Image"). Regular nodes
use exact name matching; blueprint nodes use prefix matching since their
filenames include model-specific suffixes. Integrated into
`NodeLibrarySidebarTab.vue`'s `renderedRoot` computed for leaf node
labels with fallback to `display_name`. Added `essentials_category`
(z.string().optional()) to the node def schema and `ComfyNodeDefImpl` to
parse the field already sent by the backend (PR #12357).

## Review Focus

Display names are resolved only in the Essentials tab tree view
(`NodeLibrarySidebarTab.vue`), not globally, to avoid side effects on
search, bookmarks, or other views. Blueprint prefix matching is ordered
longest-first so more specific prefixes (e.g. `image_inpainting_`) match
before shorter ones (e.g. `image_edit`).

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9072-feat-add-display-name-mappings-for-Essentials-tab-nodes-30f6d73d3650817c9acdc9b0315ed0be)
by [Unito](https://www.unito.io)

src/components/sidebar/tabs/nodeLibrary/EssentialNodeCard.test.ts

@@ -44,7 +44,7 @@ describe('EssentialNodeCard', () => {
 
     return {
       key: 'test-key',
-      label: 'Test Node',
+      label: data.display_name,
       icon: 'icon-[comfy--node]',
       type: 'node',
       totalLeaves: 1,

src/components/sidebar/tabs/nodeLibrary/EssentialNodeCard.vue

@@ -1,7 +1,7 @@
 <template>
   <div
     class="group relative flex flex-col items-center justify-center py-4 px-2 rounded-2xl cursor-pointer select-none transition-colors duration-150 box-content bg-component-node-background hover:bg-secondary-background-hover border border-component-node-border aspect-square"
-    :data-node-name="node.data?.display_name"
+    :data-node-name="node.label"
     draggable="true"
     @click="handleClick"
     @dragstart="handleDragStart"
@@ -16,7 +16,7 @@
     <TextTickerMultiLine
       class="shrink-0 h-8 w-full text-xs font-bold text-foreground leading-4"
     >
-      {{ node.data?.display_name }}
+      {{ node.label }}
     </TextTickerMultiLine>
   </div>