Add automatic gain control for outgoing microphone audio.

This addresses low microphone volume issues by automatically normalizing
outgoing audio levels with dynamic range compression and soft limiting.
The AGC is always enabled and applies voice-optimized parameters to
ensure consistent audio levels are sent to other users while preserving
manual volume control for incoming audio.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

ui.go

@@ -107,6 +107,7 @@ func (b *Barnard) OnNoiseSuppressionToggle(ui *uiterm.Ui, key uiterm.Key) {
     }
 }
 
+
 func (b *Barnard) UpdateGeneralStatus(text string, notice bool) {
     if notice {
         b.UiStatus.Fg = uiterm.ColorWhite | uiterm.AttrBold
@@ -151,6 +152,7 @@ func (b *Barnard) CommandNoiseSuppressionToggle(ui *uiterm.Ui, cmd string) {
     }
 }
 
+
 func (b *Barnard) setTransmit(ui *uiterm.Ui, val int) {
     if b.Tx && val == 1 {
         return