feat: show missing node packs in Errors Tab with install support (#9213)

## Summary

Surfaces missing node pack information in the Errors Tab, grouped by
registry pack, with one-click install support via ComfyUI Manager.

## Changes

- **What**: Errors Tab now groups missing nodes by their registry pack
and shows a `MissingPackGroupRow` with pack name, node/pack counts, and
an Install button that triggers Manager installation. A
`MissingNodeCard` shows individual unresolvable nodes that have no
associated pack. `useErrorGroups` was extended to resolve missing node
types to their registry packs using the `/api/workflow/missing_nodes`
endpoint. `executionErrorStore` was refactored to track missing node
types separately from execution errors and expose them reactively.
- **Breaking**: None

## Review Focus

- `useErrorGroups.ts` — the new `resolveMissingNodePacks` logic fetches
pack metadata and maps node types to pack IDs; edge cases around partial
resolution (some nodes have a pack, some don't) produce both
`MissingPackGroupRow` and `MissingNodeCard` entries
- `executionErrorStore.ts` — the store now separates `missingNodeTypes`
state from `errors`; the deferred-warnings path in `app.ts` now calls
`setMissingNodeTypes` so the Errors Tab is populated even when a
workflow loads without executing

## Screenshots (if applicable)


https://github.com/user-attachments/assets/97f8d009-0cac-4739-8740-fd3333b5a85b


┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9213-feat-show-missing-node-packs-in-Errors-Tab-with-install-support-3126d73d36508197bc4bf8ebfd2125c8)
by [Unito](https://www.unito.io)

src/locales/en/main.json

@@ -71,6 +71,7 @@
     "error": "Error",
     "enter": "Enter",
     "enterSubgraph": "Enter Subgraph",
+    "inSubgraph": "in subgraph '{name}'",
     "resizeFromBottomRight": "Resize from bottom-right corner",
     "resizeFromTopRight": "Resize from top-right corner",
     "resizeFromBottomLeft": "Resize from bottom-left corner",
@@ -450,6 +451,9 @@
         "import_failed": "Import Failed"
       },
       "warningTooltip": "This package may have compatibility issues with your current environment"
+    },
+    "packInstall": {
+      "nodeIdRequired": "Node ID is required for installation"
     }
   },
   "importFailed": {
@@ -3136,7 +3140,23 @@
     "errorHelpGithub": "submit a GitHub issue",
     "errorHelpSupport": "contact our support",
     "resetToDefault": "Reset to default",
-    "resetAllParameters": "Reset all parameters"
+    "resetAllParameters": "Reset all parameters",
+    "missingNodePacks": {
+      "title": "Missing Node Packs",
+      "unsupportedTitle": "Unsupported Node Packs",
+      "cloudMessage": "This workflow requires custom nodes not yet available on Comfy Cloud.",
+      "ossMessage": "This workflow uses custom nodes you haven't installed yet.",
+      "installAll": "Install All",
+      "installNodePack": "Install node pack",
+      "unknownPack": "Unknown pack",
+      "installing": "Installing...",
+      "installed": "Installed",
+      "applyChanges": "Apply Changes",
+      "searchInManager": "Search in Node Manager",
+      "viewInManager": "View in Manager",
+      "collapse": "Collapse",
+      "expand": "Expand"
+    }
   },
   "errorOverlay": {
     "errorCount": "{count} ERRORS | {count} ERROR | {count} ERRORS",