[feat] Node replacement UI (#8604)

## Summary
Add node replacement UI to the missing nodes dialog. Users can select
and replace deprecated/missing nodes with compatible alternatives
directly from the dialog.

## Changes
- Classify missing nodes into **Replaceable** (quick fix) and **Install
Required** sections
- Add select-all checkbox + per-node checkboxes for batch replacement
- `useNodeReplacement` composable handles in-place node replacement on
the graph:
  - Simple replacement (configure+copy) for nodes without mapping
  - Input/output connection remapping for nodes with mapping
  - Widget value transfer via `old_widget_ids`
  - Dot-notation input handling for Autogrow/DynamicCombo
  - Undo/redo support via `changeTracker` (try/finally)
  - Title and properties preservation
- Footer UX: "Skip for Now" button when all nodes are replaceable (cloud
+ OSS)
- Auto-close dialog when all replaceable nodes are replaced and no
non-replaceable remain
- Settings navigation link from "Don't show again" checkbox
- 505-line unit test suite for `useNodeReplacement`

## Review Focus
- `useNodeReplacement.ts` — core graph manipulation logic
- `MissingNodesContent.vue` — checkbox selection state management
- `MissingNodesFooter.vue` — conditional button rendering (cloud vs OSS
vs all-replaceable)


[screen-capture.webm](https://github.com/user-attachments/assets/7dae891c-926c-4f26-987f-9637c4a2ca16)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8604-feat-Node-replacement-UI-2fd6d73d36508148a371dabb8f4115af)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/platform/settings/constants/coreSettings.ts

@@ -1202,9 +1202,9 @@ export const CORE_SETTINGS: SettingParams[] = [
   {
     id: 'Comfy.NodeReplacement.Enabled',
     category: ['Comfy', 'Workflow', 'NodeReplacement'],
-    name: 'Enable automatic node replacement',
+    name: 'Enable node replacement suggestions',
     tooltip:
-      'When enabled, missing nodes can be automatically replaced with their newer equivalents if a replacement mapping exists.',
+      'When enabled, missing nodes with known replacements will be shown as replaceable in the missing nodes dialog, allowing you to review and apply replacements.',
     type: 'boolean',
     defaultValue: false,
     experimental: true,