Is your feature request related to a problem? Please describe.

While ssr you can't get user system color theme. It not saved in cookie and browser don't send Sec-CH-Prefers-Color-Scheme

Like this #209, #204, #100

Describe the solution you'd like

Send Accept-CH: Sec-CH-Prefers-Color-Scheme on every request, and read Sec-CH-Prefers-Color-Scheme if it exist

Describe alternatives you've considered

Alternative you can save color-theme in cookie or combine this techniques

Additional context

We use code like this

const themeHeader = 'Sec-CH-Prefers-Color-Scheme';

serverInit(req: IncomingMessage, res: ServerResponse) {
  const cookies = Cookie(req, res);

  const systemTheme = req.headers[
    themeHeader.toLowerCase()
  ] as SystemThemeName;
  const userTheme = cookies.get(storeName) as ThemeName;

  if (systemTheme) this.systemTheme = systemTheme;
  if (userTheme) this.userTheme = userTheme;

  res.setHeader('Accept-CH', themeHeader);
},