Currently, create-vue generates a playwright config that has something like this in it:

{
 webServer: {
 /**
 * use the dev server by default for faster feedback loop. Use the preview
 * server on CI for more realistic testing
 */
 command: process.env.CI
 ? "vite preview --port 5173"
 : "vite dev",
 port: 5173,
 reuseExistingServer: !process.env.CI,
 }
}

Shouldn't we need to run build before preview so that the app actually exists?

I ran into problems running my tests on GitHub Actions, and it took me a while to figure out that this was the cause. See:
vitejs/vite#4572