build: fix docs deployment build

Author: chenxin-yan

apps/docs/src/content/docs/404.mdx

@@ -0,0 +1,14 @@
+---
+title: "404"
+description: "We couldn't find the page you're looking for."
+template: splash
+editUrl: false
+hero:
+  title: "404"
+  tagline: "Let’s get you back to the documentation homepage."
+  actions:
+    - text: "Go to documentation"
+      link: "/"
+---
+
+The page you're looking for doesn’t exist or might have been moved.