build: use compiled module in playground for real-world testing

- Switch from '../src/module' to '../dist/module.mjs'
- Ensures playground tests the actual built module users would receive
- Helps catch build-time issues early (as we discovered previously)
- Aligns with best practices used by major Nuxt modules

Authored by: Aaron Lippold<lippold@gmail.com>

Author: aaronlippold

playground/nuxt.config.ts

@@ -1,5 +1,5 @@
 export default defineNuxtConfig({
-  modules: ['../src/module'],
+  modules: ['../dist/module.mjs'],
   devtools: { enabled: true },
   smartscript: {
     // Module is enabled by default