- Refactor `text-*` and `bg-*` classes to use semantic color tokens such as `foreground`, `muted-foreground`, `card`, and `accent`.
- Adjust `Header`, `Footer`, and settings pages to align with the OKLCH-based design system.
- Ensure visual consistency and accessibility for both light and dark themes.
Introduce tabbed navigation for the settings page, including Profile, Password, Sessions, and Preferences sections. Add placeholders for each section with metadata and routes. Redirect `/settings` to `/settings/profile`. Integrate `AuthGuard` for settings and authenticated layouts while incorporating reusable `Header` and `Footer` components.
