Centralized management of external links (#4471)

Update the desktop guide links to make them platform and locale-aware

Edited by Terry:
Refactor external link management by introducing a centralized
useExternalLink composable with automatic locale and platform detection
for documentation URLs.

- Created useExternalLink composable - A new centralized utility for
managing all external links
- Dynamic docs URL builder (buildDocsUrl) - Automatically constructs
docs.comfy.org URLs with:
  - Locale detection (Chinese vs English)
  - Platform detection (macOS vs Windows for desktop)
  - Flexible path construction with options

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-4471-Add-platform-and-locale-aware-desktop-guide-URL-2346d73d3650815ea4a4dd64be575bbe)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Terry Jia <terryjia88@gmail.com>

src/components/dialog/content/ApiNodesSignInContent.vue

@@ -29,7 +29,10 @@
 import Button from 'primevue/button'
 import { useI18n } from 'vue-i18n'
 
+import { useExternalLink } from '@/composables/useExternalLink'
+
 const { t } = useI18n()
+const { buildDocsUrl } = useExternalLink()
 
 const { apiNodeNames, onLogin, onCancel } = defineProps<{
   apiNodeNames: string[]
@@ -38,6 +41,9 @@ const { apiNodeNames, onLogin, onCancel } = defineProps<{
 }>()
 
 const handleLearnMoreClick = () => {
-  window.open('https://docs.comfy.org/tutorials/api-nodes/faq', '_blank')
+  window.open(
+    buildDocsUrl('/tutorials/api-nodes/faq', { includeLocale: true }),
+    '_blank'
+  )
 }
 </script>