feat(01-01): initialize Nuxt 4 project with all modules

- nuxt.config.ts with compatibilityVersion 4, SSR, 6 modules
- app/app.vue and app/pages/index.vue minimal setup
- pnpm as package manager with all dependencies installed
- TypeScript strict mode enabled
- .gitignore updated for Nuxt (.nuxt, .output, .env)
- tsconfig.json extends .nuxt/tsconfig.json

app/app.vue

@@ -0,0 +1,6 @@
+<template>
+  <div>
+    <NuxtRouteAnnouncer />
+    <NuxtPage />
+  </div>
+</template>