Add individual volume control for audio devices

Added individual volume control for each device in the Realtime UDP Audio Improvements section.

Author: RaspberryFpc

CHANGELOG.md

@@ -7,7 +7,7 @@ All notable changes to this project are documented in this file.
 - Removed buffer duplication for direct packet processing.
 - Switched to poll-based waiting for cleaner and more efficient socket handling.
 - On USB audio devices, ALSA buffer times below 2.5 ms are now achievable.
-
+- Individual volume control for each device.
 
 ## [1.0.13] – 2026-03-15
 ### Bugfix