/claim #1643

• Added a mic mute/unmute toggle button to the app header.
• Dropdown menu for timed mute (30min, 1h, 2h).
• Click-outside-to-close support.
• Accessibility improvements.
• Smooth transitions for color/icon changes.
• State persists with localStorage, auto-unmute on timer expiry.

Fixes #1643

https://github.com/user-attachments/assets/537480fe-8489-4b4a-b08e-97276e1d7652