feat: Add validation viewing functionality and UI updates

- Implemented a new function to mark validations as viewed by the user, updating the validation state accordingly.
- Added a new API endpoint for marking validations as viewed, integrated with the existing GitHub routes.
- Enhanced the sidebar to display the count of unviewed validations, providing real-time updates.
- Updated the GitHub issues view to mark validations as viewed when issues are accessed, improving user interaction.
- Introduced a visual indicator for unviewed validations in the issue list, enhancing user awareness of pending validations.

apps/ui/src/components/layout/sidebar/hooks/index.ts

@@ -10,3 +10,4 @@ export { useProjectCreation } from './use-project-creation';
 export { useSetupDialog } from './use-setup-dialog';
 export { useTrashDialog } from './use-trash-dialog';
 export { useProjectTheme } from './use-project-theme';
+export { useUnviewedValidations } from './use-unviewed-validations';