Fix desktop menu docs links regression (#7181)

## Summary
- make `useExternalLink` rely on the global i18n locale so it can be
used safely outside setup
- restore `electronAdapter` to use the shared `useExternalLink` helper
for docs URLs and static links

## Motivation
Desktop menu items disappeared because a top-level call to
`useExternalLink` in `electronAdapter` triggered `useI18n` at
module-eval time, throwing and blocking extension registration. By
making the composable global-locale-only and using it in
`electronAdapter`, the module can load without setup context while
preserving link behavior.

## Testing
- pnpm typecheck
- pnpm lint:fix

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7181-Fix-desktop-menu-docs-links-regression-2c06d73d36508157ae48cff078b9173e)
by [Unito](https://www.unito.io)

src/composables/useExternalLink.ts

@@ -1,7 +1,7 @@
 import { computed } from 'vue'
 
 import { electronAPI, isElectron } from '@/utils/envUtil'
-import { useI18n } from 'vue-i18n'
+import { i18n } from '@/i18n'
 
 /**
  * Composable for building docs.comfy.org URLs with automatic locale and platform detection
@@ -23,7 +23,7 @@ import { useI18n } from 'vue-i18n'
  * ```
  */
 export function useExternalLink() {
-  const { locale } = useI18n()
+  const locale = computed(() => String(i18n.global.locale.value))
 
   const isChinese = computed(() => {
     return locale.value === 'zh' || locale.value === 'zh-TW'