{{--
Dark mode and color scheme initialization - MUST be included at the very top of ,
BEFORE any CSS/Vite tags, to prevent white flash on page load.
1. The blocking script applies the 'dark' class, data-color-scheme, and data-loading to synchronously.
2. The style tag covers background, text color, color-scheme, x-cloak hiding, and transition
suppression so the first paint matches the user's theme with zero flash.
--}}