feat(docs): migrate bs docs

blocksuite/docs-site/.vitepress/theme/composables/use-posts.ts

@@ -0,0 +1,19 @@
+import { useRoute } from 'vitepress';
+import { computed } from 'vue';
+
+import { data as posts } from './posts.data';
+
+export function usePosts() {
+  const route = useRoute();
+  const path = route.path;
+
+  function findCurrentIndex() {
+    const result = posts.findIndex(p => p.url === route.path);
+    if (result === -1) console.error(`blog post missing: ${route.path}`);
+    return result;
+  }
+
+  const post = computed(() => posts[findCurrentIndex()]);
+
+  return { posts, post, path };
+}