Add blog app scaffolding with remark plugins

apps/blog/src/plugins/remark-aside.ts

@@ -0,0 +1,14 @@
+import { visit } from 'unist-util-visit';
+import type { Root } from 'mdast';
+
+export default function remarkAside() {
+  return (tree: Root) => {
+    visit(tree, 'textDirective', (node: any) => {
+      if (node.name !== 'aside') return;
+
+      const data = node.data || (node.data = {});
+      data.hName = 'span';
+      data.hProperties = { class: 'aside' };
+    });
+  };
+}