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).

tsconfig.json

@@ -22,7 +22,13 @@
     "verbatimModuleSyntax": true,
     "baseUrl": ".",
     "paths": {
-      "@/*": ["src/*"]
+      "@/*": ["src/*"],
+      "@/utils/formatUtil": [
+        "packages/shared-frontend-utils/src/formatUtil.ts"
+      ],
+      "@/utils/networkUtil": [
+        "packages/shared-frontend-utils/src/networkUtil.ts"
+      ]
     },
     "typeRoots": ["src/types", "node_modules/@types"],
     "outDir": "./dist",