fix: export @nuxt/scripts/registry for build-time integrations

Relates to nuxt/nuxt#27010

Author: harlan-zw

build.config.ts

@@ -0,0 +1,7 @@
+import { defineBuildConfig } from 'unbuild'
+
+export default defineBuildConfig({
+  entries: [
+    './src/registry',
+  ],
+})

package.json

@@ -22,6 +22,10 @@
       "types": "./dist/types.d.ts",
       "import": "./dist/module.mjs",
       "require": "./dist/module.cjs"
+    },
+    "./registry": {
+      "types": "./dist/registry.d.ts",
+      "import": "./dist/registry.mjs"
     }
   },
   "main": "./dist/module.cjs",