## Problem
- We still use/maintain the legacy theming even though we moved to
Shadcn
- We have two themes list with similar code
## Solution
- Migrate some components to `cva` and `cn` instead of `styleHandler`
- Remove redundant `themes` in favor of `singleThemes`
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Bug Fixes**
* Standardized theme selection across the app so theme menus
consistently offer the same light/dark/system options, including
dropdowns, navigation menus, and command menus.
* **Refactor**
* Refreshed styling for multiple shared UI components (menus, tabs, side
panels, loading indicators, icons, and modal dialogs) to improve
consistency while preserving visual behavior.
* **Chores**
* Improved the UI patterns CI “validate exports” check for clearer
failure output when exports change unexpectedly.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
## Problem
With #45211 and #45218 merged, we don't need the `_Shadcn_` suffix
anymore
## Solution
- [x] Remove the `_Shadcn_` suffix
- [x] Update exports and imports
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Refactor**
* Standardized UI component exports by removing legacy naming
conventions and providing direct imports for checkbox and radio group
components throughout the design system.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
Sorted all imports in all packages, `cms`, `design-system` and
`ui-library` apps by running `pnpm format` on them.
All changes in this PR are done by the script.
Gildas Garcia