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>

ts3-client/README.md

@@ -38,6 +38,8 @@ Android app in [`../android`](../android) does.
   four levels) → **typing attenuation** (the transient suppressor, told about key presses)
   → **automatic gain control** (AGC2, WebRTC's successor to the AGC1 TS3 uses). Checked
   against WebRTC built from source.
+  - **Boost quiet speech** (0–20 dB) raises AGC2's cap on the amplified noise floor, which
+    otherwise holds back a distant voice that is barely above the background noise.
   - Echo cancellation (WebRTC AEC3) is intentionally omitted — it needs the loudspeaker
     reference signal and matters mainly for open speakers, not the typical headset.
 - **Push-to-Talk** — bind any key or mouse button as a global hotkey; transmits only while held.