Function apply_enable 

pub fn apply_enable(
    stored: &LogForwardConfig,
    request: &LogForwardEnableRequest,
) -> Result<LogForwardConfig>

Merge a request onto the stored config and validate the result.

Kept out of both the HTTP handler and the CLI so the two paths cannot drift: enable means the same thing whether it arrives over the daemon’s API or is written straight to disk with the daemon stopped.