feat: warn when dev server listens on a restricted port

If the port assigned to the Vite dev server is categorised as restricted
by browsers (e.g. port 6000), a warning is now displayed in the console
to prevent accessibility issues.

package.json

@@ -0,0 +1,14 @@
+{
+  "name": "vite-plugin-port-checker",
+  "version": "1.0.0",
+  "description": "",
+  "main": "dist/index.js",
+  "scripts": {
+    "build": "tsc"
+  },
+  "devDependencies": {
+    "prettier": "^3.8.3",
+    "typescript": "^5.5.3"
+  },
+  "private": true
+}