fix: show Missing Nodes dialog for missing node prompt errors (#8511)

## Summary
When a workflow is queued with a missing node type, show the Missing
Nodes dialog instead of a generic error toast. This gives users
actionable options like "Open Manager" and "Install All".

## Changes
- Detect `missing_node_type` error from backend in `queuePrompt()` catch
block
- Construct `MissingNodeType` object with class type and contextual hint
- Reuse existing `showMissingNodesError()` to trigger the dialog

## Dependencies
⚠️ **Requires backend PR:**
https://github.com/Comfy-Org/ComfyUI/pull/12177

The backend PR changes the error type from `invalid_prompt` to
`missing_node_type` and adds `extra_info` with node details.

## Related
- Fixes COM-12528
- Addresses ~49 GitHub issues with confusing "missing class_type" errors

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8511-fix-show-Missing-Nodes-dialog-for-missing-node-prompt-errors-2f96d73d3650812b95f0f08e51abaabb)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>

src/scripts/app.ts

@@ -70,6 +70,8 @@ import type { ComfyExtension, MissingNodeType } from '@/types/comfy'
 import { type ExtensionManager } from '@/types/extensionTypes'
 import type { NodeExecutionId } from '@/types/nodeIdentification'
 import { graphToPrompt } from '@/utils/executionUtil'
+import type { MissingNodeTypeExtraInfo } from '@/workbench/extensions/manager/types/missingNodeErrorTypes'
+import { createMissingNodeTypeFromError } from '@/workbench/extensions/manager/utils/missingNodeErrorUtil'
 import { anyItemOverlapsRect } from '@/utils/mathUtil'
 import { collectAllNodes, forEachNode } from '@/utils/graphTraversalUtil'
 import {
@@ -1394,10 +1396,21 @@ export class ComfyApp {
               } catch (error) {}
             }
           } catch (error: unknown) {
-            useDialogService().showErrorDialog(error, {
-              title: t('errorDialog.promptExecutionError'),
-              reportType: 'promptExecutionError'
-            })
+            if (
+              error instanceof PromptExecutionError &&
+              typeof error.response.error === 'object' &&
+              error.response.error?.type === 'missing_node_type'
+            ) {
+              const extraInfo = (error.response.error.extra_info ??
+                {}) as MissingNodeTypeExtraInfo
+              const missingNodeType = createMissingNodeTypeFromError(extraInfo)
+              this.showMissingNodesError([missingNodeType])
+            } else {
+              useDialogService().showErrorDialog(error, {
+                title: t('errorDialog.promptExecutionError'),
+                reportType: 'promptExecutionError'
+              })
+            }
             console.error(error)
 
             if (error instanceof PromptExecutionError) {