fix og (#515)

docs/src/app/og/[...slug]/route.tsx

@@ -0,0 +1,16 @@
+import { NextResponse } from "next/server";
+import { getPageTitle, renderOgImage } from "../og-image";
+
+export async function GET(
+  _request: Request,
+  { params }: { params: Promise<{ slug: string[] }> },
+) {
+  const { slug } = await params;
+  const title = getPageTitle(slug.join("/"));
+
+  if (!title) {
+    return NextResponse.json({ error: "Not found" }, { status: 404 });
+  }
+
+  return renderOgImage(title);
+}