Let AGC raise the noise floor further to bring up a distant voice

AGC2 won't amplify the background noise above -50 dBFS, which also caps
the gain for a voice barely above that noise: a distant talker ended up
5 dB quieter than a near one with noise suppression on, 12 dB with it
off. A "Boost quiet speech" setting (0-20 dB, default 0) raises the cap,
live, on desktop and Android.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

android/app/src/main/java/com/ts3client/android/ui/SettingsScreen.kt

@@ -167,6 +167,12 @@ fun SettingsScreen(vm: SessionController, onBack: () -> Unit) {
                 agc = it
                 change { this.agc = it }
             }
+            if (agc) {
+                Level("Boost quiet speech", settings.agcBoostDb.toFloat(), 0f..Settings.MAX_AGC_BOOST_DB.toFloat(),
+                    { "+${it.roundToInt()} dB" }, steps = Settings.MAX_AGC_BOOST_DB - 1) {
+                    change { agcBoostDb = it.roundToInt() }
+                }
+            }
 
             Section("Playback")
             Level("Volume", settings.outputVolume.toFloat(), 0f..2f, { "${(it * 100).roundToInt()} %" }) {