Refactor docs to use Nuxt Content v3 and file-based pages

Migrates documentation from markdown-based content to Nuxt Content v3 with file-based routing. Removes old markdown content files, adds new Vue page components, updates layout and content rendering logic, introduces a Prose wrapper, and updates dependencies for Nuxt Content v3 and related packages.

docs/pages/contributors.vue

@@ -0,0 +1,12 @@
+<script setup lang="ts"></script>
+
+<template>
+  <main>
+    <h1>Contributors</h1>
+
+    <p>
+      Vue Select is supported by a community of awesome contributors! Without
+      their contributions, the package would not be what it is today.
+    </p>
+  </main>
+</template>