feat(settings): add appearance settings with dark mode toggle and translations

- Introduced new appearance settings page with a dark mode toggle feature.
- Added localization support for English, Spanish, and Portuguese in appearance settings.
- Removed the ThemeSelector component and updated PreferenceSelector accordingly.

worklenz-frontend/src/features/theme/ThemeSelector.tsx

@@ -1,28 +0,0 @@
-// ThemeSelector.tsx
-import { Button } from 'antd';
-import React from 'react';
-import { useAppDispatch } from '@/hooks/useAppDispatch';
-import { useAppSelector } from '@/hooks/useAppSelector';
-import { toggleTheme } from './themeSlice';
-import { MoonOutlined, SunOutlined } from '@ant-design/icons';
-
-const ThemeSelector = () => {
-  const themeMode = useAppSelector(state => state.themeReducer.mode);
-  const dispatch = useAppDispatch();
-
-  const handleDarkModeToggle = () => {
-    dispatch(toggleTheme());
-  };
-
-  return (
-    <Button
-      type={themeMode === 'dark' ? 'primary' : 'default'}
-      icon={themeMode === 'dark' ? <SunOutlined /> : <MoonOutlined />}
-      shape="circle"
-      onClick={handleDarkModeToggle}
-      className="transition-all duration-300" // Optional: add smooth transition
-    />
-  );
-};
-
-export default ThemeSelector;