Add a global volume button in the header component: - Show "volume_up" icon when global volume is on - Show "volume_off" icon when global volume is off - Save volume state in localStorage, key: "globalVolume" <img width="847" height="407" alt="Image" src="https://github.com/user-attachments/assets/b0b3c954-f3c8-42e9-929d-6586f7cf8ef3" /> <img width="847" height="407" alt="Image" src="https://github.com/user-attachments/assets/5fd33556-428e-48f0-8fb3-ce8c029a576e" />
Add a global volume button in the header component: