fix: feed VAD the raw mic track captured before setProcessor

After setProcessor resolves, track.mediaStreamTrack returns the processed
(noise-gated) track. The VAD was seeing gated silence, closing immediately,
and deadlocking with both gates closed. Capture the raw MediaStreamTrack
before calling setProcessor and pass that to SileroVADGate instead.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/state/CallViewModel/localMember/Publisher.ts

@@ -440,6 +440,7 @@ export class Publisher {
     let transformer: NoiseGateTransformer | null = null;
     let audioCtx: AudioContext | null = null;
     let vadGate: SileroVADGate | null = null;
+    let rawMicTrack: MediaStreamTrack | null = null;
 
     const currentParams = (): NoiseGateParams => ({
       threshold: noiseGateThreshold.getValue(),
@@ -460,14 +461,8 @@ export class Publisher {
       transformer?.setVADOpen(true);
     };
 
-    const startVAD = (track: LocalAudioTrack, ctx: AudioContext): void => {
+    const startVAD = (rawTrack: MediaStreamTrack, ctx: AudioContext): void => {
       stopVAD();
-      // eslint-disable-next-line @typescript-eslint/no-explicit-any
-      const rawTrack: MediaStreamTrack | undefined = (track as any).mediaStreamTrack;
-      if (!rawTrack) {
-        this.logger.warn("[VAD] no underlying MediaStreamTrack — skipping VAD");
-        return;
-      }
       const stream = new MediaStream([rawTrack]);
       vadGate = new SileroVADGate(stream, ctx, {
         positiveThreshold: vadPositiveThreshold.getValue(),
@@ -488,6 +483,9 @@ export class Publisher {
         if (enabled && !audioTrack.getProcessor()) {
           const params = currentParams();
           this.logger.info("[NoiseGate] attaching processor, params:", params);
+          // Capture the raw mic track BEFORE setProcessor replaces it
+          // eslint-disable-next-line @typescript-eslint/no-explicit-any
+          rawMicTrack = (audioTrack as any).mediaStreamTrack ?? null;
           transformer = new NoiseGateTransformer(params);
           audioCtx = new AudioContext();
           this.logger.info("[NoiseGate] AudioContext state before resume:", audioCtx.state);
@@ -500,7 +498,7 @@ export class Publisher {
               .setProcessor(transformer as any);
           }).then(() => {
             this.logger.info("[NoiseGate] setProcessor resolved");
-            if (vadEnabled.getValue() && audioCtx) startVAD(audioTrack, audioCtx);
+            if (vadEnabled.getValue() && audioCtx && rawMicTrack) startVAD(rawMicTrack, audioCtx);
           }).catch((e: unknown) => {
             this.logger.error("[NoiseGate] setProcessor failed", e);
           });
@@ -511,6 +509,7 @@ export class Publisher {
           void audioCtx?.close();
           audioCtx = null;
           transformer = null;
+          rawMicTrack = null;
           // eslint-disable-next-line @typescript-eslint/no-explicit-any
           (audioTrack as any).setAudioContext(undefined);
         } else {
@@ -522,9 +521,9 @@ export class Publisher {
     combineLatest([audioTrack$, vadEnabled.value$])
       .pipe(scope.bind())
       .subscribe(([audioTrack, enabled]) => {
-        if (!audioTrack || !audioCtx) return;
+        if (!audioCtx || !rawMicTrack) return;
         if (enabled) {
-          startVAD(audioTrack, audioCtx);
+          startVAD(rawMicTrack, audioCtx);
         } else {
           stopVAD();
         }