fix: remove continuous sleep mode check to prevent audio interference

The continuous ensure_sleep_mode_disabled() call in the format detection
loop caused repeated I2C transactions to the TC358743, disrupting HDMI
audio capture. Sleep mode is already disabled once during video_init(),
which is sufficient.

internal/native/cgo/video.c

@@ -752,7 +752,6 @@ void *run_detect_format(void *arg)
 
     while (!should_exit)
     {
-        ensure_sleep_mode_disabled();
 
         memset(&dv_timings, 0, sizeof(dv_timings));
         if (ioctl(sub_dev_fd, VIDIOC_QUERY_DV_TIMINGS, &dv_timings) != 0)

ui/src/routes/devices.$id.tsx

@@ -534,6 +534,7 @@ export default function KvmIdRoute() {
 
     const audioTransceiver = pc.addTransceiver("audio", { direction: "sendrecv" });
 
+    if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
       navigator.mediaDevices.getUserMedia({
         audio: {
           echoCancellation: true,
@@ -549,6 +550,9 @@ export default function KvmIdRoute() {
       }).catch((err) => {
         console.warn("Microphone access denied or unavailable:", err.message);
       });
+    } else {
+      console.warn("navigator.mediaDevices.getUserMedia is not available in this browser/context");
+    }
 
     const rpcDataChannel = pc.createDataChannel("rpc");
     rpcDataChannel.onclose = () => console.log("rpcDataChannel has closed");