Add Auto Theme Mode (Match System Theme)

[clicktodev]

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

The theme setting currently only supports manual selection between light and dark modes. This becomes inconvenient when my operating system is already configured to switch themes automatically. The site ends up out of sync with the system theme, breaking consistency across applications.

Describe the solution you'd like

Introduce a “system” theme option that follows the OS-level theme preference using prefers-color-scheme. When the system switches between light and dark, the site should automatically update without requiring user interaction.

Describe alternatives you've considered

No response

Additional context

Many modern frameworks and apps support a system-synced theme option. Adding this would improve accessibility and provide a more seamless user experience.

Validations

• Follow our Code of Conduct
• Read the docs.
• Read the Contributing Guidelines.
• Check that there isn't already an issue that asks for the same feature to avoid creating a duplicate.