fix(lotus): don't start two denoise processors on racing LocalTrackPublished

apply() guarded on mic.getProcessor(), which is only set after setProcessor()
resolves (after the whole wasm/model load), so mic-published followed by
camera-published constructed two processors — two AudioContexts, two model
loads, double lock hold time. Track the in-flight processor per room, skip
apply() while one is pending, and destroy a pending processor if the module
is torn down before setProcessor resolves. Unit-tested.

Fixes #10

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/lotus/lotusDenoise.ts

@@ -97,13 +97,29 @@ export function startLotusDenoise(vm: CallViewModel): () => void {
     room.localParticipant.getTrackPublication(Track.Source.Microphone)
       ?.track as LocalAudioTrack | undefined;
 
+  // [lotus] `mic.getProcessor()` only becomes set once `setProcessor()`
+  // resolves — i.e. after the whole wasm/model load. LiveKit fires
+  // `LocalTrackPublished` once per local track (mic, then camera on join with
+  // video), so two calls to `apply()` can both observe `!mic.getProcessor()`
+  // and race to construct a second `LotusDenoiseProcessor` (a second
+  // AudioContext + model load) before the first has attached. Track an
+  // in-flight setProcessor per room and skip `apply()` while one is pending.
+  const pendingProcessors = new Map<LivekitRoom, LotusDenoiseProcessor>();
+
   const apply = (room: LivekitRoom): void => {
     const mic = micOf(room);
-    if (mic && !mic.getProcessor()) {
-      void mic
-        .setProcessor(new LotusDenoiseProcessor(config))
-        .catch((e) => logger.warn("[lotus] denoise setProcessor failed", e));
-    }
+    if (!mic || mic.getProcessor() || pendingProcessors.has(room)) return;
+    const processor = new LotusDenoiseProcessor(config);
+    pendingProcessors.set(room, processor);
+    void mic
+      .setProcessor(processor)
+      .catch((e) => logger.warn("[lotus] denoise setProcessor failed", e))
+      .finally(() => {
+        // Only clear if we're still the pending entry (a teardown that ran
+        // while this was in flight may have already replaced/removed it).
+        if (pendingProcessors.get(room) === processor)
+          pendingProcessors.delete(room);
+      });
   };
 
   const roomListeners = new Map<LivekitRoom, () => void>();
@@ -149,6 +165,15 @@ export function startLotusDenoise(vm: CallViewModel): () => void {
     for (const room of rooms) {
       const mic = micOf(room);
       if (mic?.getProcessor()) void mic.stopProcessor();
+      else {
+        // [lotus] A setProcessor() call may still be in flight (mid wasm/model
+        // load) when teardown runs, in which case `mic.getProcessor()` is
+        // still undefined and `stopProcessor()` above is a no-op. Destroy the
+        // pending processor directly so its AudioContext/graph don't leak.
+        const pending = pendingProcessors.get(room);
+        if (pending) void pending.destroy().catch(() => undefined);
+      }
     }
+    pendingProcessors.clear();
   };
 }