Automatic Theme Switching

Hey Fluent Community team, let's add automatic theme switching for a better user experience. For example, when a member logs in at night with their device in dark mode, the site auto-switches to dark theme—no blinding light! Keep the manual toggle and use prefers-color-scheme for seamless system-based switching.

VOTE: https://community.wpmanageninja.com/fluentcommunity-roadmp/#/idea/1039/