[Bug report] add extra pages seems to have no effect about vuepress-next

[Mister-Hope]

/hello.html

[yzqdev]

/hello.html

It works for extra page, thank you.

[yzqdev]

common usage (2.0.0-rc.2)

I just downgrade vuepress to 2.0.0-rc.2 the function router.addRoute to add a route works.
while update to 2.0.0-rc3 the added route is not found

repo

client.ts

export default defineClientConfig({
  enhance({ app, router, siteData }) {
    app.component("Hello", Hello);
    router.addRoute({
      path: "/hi",
      name: "hi",
      component: Hello,
    });
  },
});

the router.addRoute added page (vuepress version 2.0.0-rc.2)
https://yzqbugs.github.io/vuepress-bugs/hi

the #1447 custom routes pr seems to break common usage

the reproduction repo (2.0.0-rc3)

https://stackblitz.com/edit/vuepress-ccylja?file=docs%2F.vuepress%2Fclient.ts,docs%2F.vuepress%2FHello.vue,docs%2FREADME.md

click the to hi page button , /hi not found