Toggle for Dark and Light Mode

**Overview:**
Implement a user-friendly toggle switch in the settings menu to allow users to easily switch between dark and light mode for the application. This feature will enhance user experience by providing customization options based on individual preferences and ambient lighting conditions.

**Requirements:**
1. **Toggle Switch:**
- A clear, intuitive toggle button in the settings menu labeled "Dark Mode" or "Light Mode."
- The toggle should indicate the current mode (e.g., using a sun/moon icon).

2. **Functionality:**
- When the toggle is activated, the application’s theme should switch instantly between dark and light mode.
- The user’s preference should be saved, ensuring the chosen mode persists across app sessions.