fix: show correct empty state on Missing tab instead of misleading registry error (#9640)

## Summary

Show tab-specific empty state messages instead of a misleading registry
connection error on tabs that don't depend on the Manager API.

## Changes

- **What**: Scoped `comfyManagerStore.error` to only affect tabs that
actually use the Manager API (AllInstalled, UpdateAvailable,
Conflicting). Missing and Workflow tabs use the registry directly, so
the Manager API error is irrelevant to them. Previously, any prior
Manager API failure would cause `"Error connecting to the Comfy Node
Registry"` to appear on the Missing tab even when there are simply no
missing nodes.

## Review Focus

The `isManagerErrorRelevant` computed only shows the error for Manager
API-dependent tabs. Verify that AllInstalled/UpdateAvailable/Conflicting
still correctly show the error when Manager API fails.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9640-fix-show-correct-empty-state-on-Missing-tab-instead-of-misleading-registry-error-31e6d73d365081868da1d226a9bb5fdc)
by [Unito](https://www.unito.io)

src/workbench/extensions/manager/components/manager/ManagerDialog.vue

@@ -402,7 +402,7 @@ const isUnresolvedTab = computed(
 )
 
 // Map of tab IDs to their empty state i18n key suffixes
-const tabEmptyStateKeys: Partial<Record<ManagerTab, string>> = {
+const tabEmptyStateKeys: Record<string, string> = {
   [ManagerTab.AllInstalled]: 'allInstalled',
   [ManagerTab.UpdateAvailable]: 'updateAvailable',
   [ManagerTab.Conflicting]: 'conflicting',
@@ -410,12 +410,27 @@ const tabEmptyStateKeys: Partial<Record<ManagerTab, string>> = {
   [ManagerTab.Missing]: 'missing'
 }
 
+const managerApiDependentTabs = new Set<string>([
+  ManagerTab.AllInstalled,
+  ManagerTab.UpdateAvailable,
+  ManagerTab.Conflicting,
+  ManagerTab.NotInstalled,
+  ManagerTab.Missing
+])
+
+const isManagerErrorRelevant = computed(() => {
+  const tabId = selectedTab.value?.id
+  return (
+    !!comfyManagerStore.error && !!tabId && managerApiDependentTabs.has(tabId)
+  )
+})
+
 // Empty state messages based on current tab and search state
 const emptyStateTitle = computed(() => {
-  if (comfyManagerStore.error) return t('manager.errorConnecting')
+  if (isManagerErrorRelevant.value) return t('manager.errorConnecting')
   if (searchQuery.value) return t('manager.noResultsFound')
 
-  const tabId = selectedTab.value?.id as ManagerTab | undefined
+  const tabId = selectedTab.value?.id
   const emptyStateKey = tabId ? tabEmptyStateKeys[tabId] : undefined
 
   return emptyStateKey
@@ -424,7 +439,7 @@ const emptyStateTitle = computed(() => {
 })
 
 const emptyStateMessage = computed(() => {
-  if (comfyManagerStore.error) return t('manager.tryAgainLater')
+  if (isManagerErrorRelevant.value) return t('manager.tryAgainLater')
   if (searchQuery.value) {
     const baseMessage = t('manager.tryDifferentSearch')
     if (isLegacyManagerSearch.value) {
@@ -433,7 +448,7 @@ const emptyStateMessage = computed(() => {
     return baseMessage
   }
 
-  const tabId = selectedTab.value?.id as ManagerTab | undefined
+  const tabId = selectedTab.value?.id
   const emptyStateKey = tabId ? tabEmptyStateKeys[tabId] : undefined
 
   return emptyStateKey