fix(icom): the audio stream no longer depends on the speakers

The sink — decode + recorder feed — was built only on the success path of
starting the monitor, so speakers-off (the remembered preference) or an
output device that failed to open silently disabled the WHOLE stream: the
session connected audio=false, and a ticked RX-audio checkbox did nothing.
The sink now exists whenever the stream is on; only the monitor obeys the
speaker choice.

app.go

@@ -15637,6 +15637,25 @@ func (a *App) reloadCAT() {
 			// verification (see icomaudio.go) — hence experimental + opt-in.
 			acfg, _ := a.GetAudioSettings()
 			a.audioMgr.StopMonitor() // clear any prior monitor/sink so a re-save restarts cleanly
+			// The SINK — decode + recorder feed — exists whenever the stream is
+			// on. It used to be built only when the speakers were also wanted,
+			// so "speakers off" (or a sink that failed to open) silently turned
+			// the whole stream off: audio=false on the wire, no recordings, no
+			// voice keyer, and a ticked RX-audio checkbox that did nothing.
+			codec := audio.NewPCM16Codec()
+			audioSink = func(payload []byte) {
+				pcm, err := codec.Decode(payload)
+				if err != nil {
+					return
+				}
+				a.audioMgr.PushMonitorAudio(pcm)
+				// And to the QSO recorder, which has no device to capture from
+				// on this backend. It drops the samples unless a recording is
+				// actually running, so this costs a function call when idle.
+				if a.qsoRec != nil {
+					a.qsoRec.PushRX(pcm)
+				}
+			}
 			// Listening is a CHOICE, remembered: an operator sitting next to the
 			// radio hears it in the room and wants the stream only for the
 			// recorder and the voice keyer. Stop listening turns this off, the
@@ -15645,36 +15664,8 @@ func (a *App) reloadCAT() {
 			if a.settingOr(keyAudioMonitorOn, "1") != "1" {
 				applog.Printf("icom-net audio: stream on, speakers off (Listening was stopped by the operator)")
 			} else if err := a.audioMgr.StartMonitorSink(acfg.ListeningDevice); err != nil {
-				applog.Printf("icom-net audio: cannot start output sink: %v", err)
+				applog.Printf("icom-net audio: stream on, but the output sink failed: %v", err)
 			} else {
-				codec := audio.NewPCM16Codec()
-				audioSink = func(payload []byte) {
-					pcm, err := codec.Decode(payload)
-					if err != nil {
-						return
-					}
-					// The IC-7760 streams TWO-channel LPCM whatever the conninfo
-					// asks for (rxcodec 0x02 was requested, 1280-byte payloads
-					// kept arriving — 320 stereo frames per 20 ms tick, right
-					// channel all zeros). Played as mono that is half-speed
-					// metallic garble. A stereo-sized packet is folded to its
-					// left channel; a 640-byte mono packet (a rig that honours
-					// the request) passes through untouched.
-					if len(pcm) == 1280 {
-						mono := make([]byte, len(pcm)/2)
-						for i := 0; i+3 < len(pcm); i += 4 {
-							mono[i/2], mono[i/2+1] = pcm[i], pcm[i+1]
-						}
-						pcm = mono
-					}
-					a.audioMgr.PushMonitorAudio(pcm)
-					// And to the QSO recorder, which has no device to capture from
-					// on this backend. It drops the samples unless a recording is
-					// actually running, so this costs a function call when idle.
-					if a.qsoRec != nil {
-						a.qsoRec.PushRX(pcm)
-					}
-				}
 				applog.Printf("icom-net audio: RX audio streaming ENABLED (experimental) → %q", acfg.ListeningDevice)
 			}
 		}