docs: add roadmap page with volta board

docs/components/content/VoltaEmbed.vue

@@ -0,0 +1,14 @@
+<template>
+  <iframe :src="src" class="w-full min-h-[calc(100vh/1.5)] border border-gray-200 dark:border-gray-800 rounded-md" />
+</template>
+
+<script setup lang="ts">
+const props = defineProps({
+  token: {
+    type: String,
+    required: true
+  }
+})
+
+const src = computed(() => `https://volta.net/embed/${props.token}`)
+</script>

docs/content/1.getting-started/5.roadmap.md

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+---
+title: Roadmap
+description: Discover our Volta board for @nuxthq/ui development status.
+toc: false
+---
+
+:volta-embed{token="eyJ2aWV3IjoiYm9hcmQiLCJib2FyZFN0YXR1c2VzIjpbInRyaWFnZSIsImJhY2tsb2ciLCJ0b2RvIiwiaW5fcHJvZ3Jlc3MiLCJpbl9yZXZpZXciLCJkb25lIiwicmVsZWFzZWQiXSwiYm9hcmRMaW5rZWRQcnMiOnRydWUsImxpc3RHcm91cCI6InN0YXRlIiwibGlzdE9yZGVyIjoiY3JlYXRlZF9hdCIsInRpbWVsaW5lWm9vbSI6Im1vbnRoIiwidGltZWxpbmVPcmRlciI6InN0YXRlIiwidGltZWxpbmVEaXNwbGF5IjoiYWxsX21pbGVzdG9uZXMiLCJmaWx0ZXJzIjp7fSwib3duZXIiOiJudXh0bGFicyIsIm5hbWUiOiJ1aSJ9"}