Extract shared utilities into workspace package (#5843)

## Summary

Extracts shared formatting and network utilities into dedicated
workspace package.

## Changes

- **What**: Created `@comfyorg/shared-frontend-utils` package containing
formatUtil and networkUtil
- **Breaking**: None - utilities remain accessible via path aliases in
`tsconfig`

Split `createAnnotatedPath` and `electronMirrorCheck` out and left in
frontend, due to their tightly-coupled nature. See [discussion on this
PR](https://github.com/Comfy-Org/ComfyUI_frontend/pull/5843#issuecomment-3344724727).

src/components/install/mirror/MirrorItem.vue

@@ -60,8 +60,8 @@ import { computed, onMounted, ref, watch } from 'vue'
 import UrlInput from '@/components/common/UrlInput.vue'
 import type { UVMirror } from '@/constants/uvMirrors'
 import { st } from '@/i18n'
+import { checkMirrorReachable } from '@/utils/electronMirrorCheck'
 import { normalizeI18nKey } from '@/utils/formatUtil'
-import { checkMirrorReachable } from '@/utils/networkUtil'
 import { ValidationState } from '@/utils/validationUtil'
 
 const FILE_URL_SCHEME = 'file://'