Fix audio visual & mute control when using Hyprnote without headphone

- Currently we use Mic stream to capture both.
- Only single channel is visualized.

Actually this two channel can be just merged in UI.

<img width="373" height="175" alt="Image" src="https://github.com/user-attachments/assets/f9a0d199-9aa2-4ee1-ba16-1fc9cbfe6076" />