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/components/rightSidePanel/parameters/SectionWidgets.vue

@@ -131,6 +131,12 @@ const nodeHasError = computed(() => {
   return hasDirectError.value || hasContainerInternalError.value
 })
 
+const showSeeError = computed(
+  () =>
+    nodeHasError.value &&
+    useSettingStore().get('Comfy.RightSidePanel.ShowErrorsTab')
+)
+
 const parentGroup = computed<LGraphGroup | null>(() => {
   if (!targetNode.value || !getNodeParentGroup) return null
   return getNodeParentGroup(targetNode.value)
@@ -194,6 +200,7 @@ defineExpose({
       :enable-empty-state
       :disabled="isEmpty"
       :tooltip
+      :size="showSeeError ? 'lg' : 'default'"
     >
       <template #label>
         <div class="flex flex-wrap items-center gap-2 flex-1 min-w-0">
@@ -223,13 +230,10 @@ defineExpose({
             </span>
           </span>
           <Button
-            v-if="
-              nodeHasError &&
-              useSettingStore().get('Comfy.RightSidePanel.ShowErrorsTab')
-            "
+            v-if="showSeeError"
             variant="secondary"
             size="sm"
-            class="shrink-0 rounded-lg text-sm"
+            class="shrink-0 rounded-lg text-sm h-8"
             @click.stop="navigateToErrorTab"
           >
             {{ t('rightSidePanel.seeError') }}