feat: RNNoise WASM AudioWorklet for ML-based noise suppression (Phase 3)

Inject @sapphi-red/web-noise-suppressor into AudioManager's input pipeline
as a toggleable AudioWorkletNode. The worklet is loaded lazily on first
enable, then kept alive — toggling bypasses by rewiring the graph without
destroying the WASM instance. Browser NS is forced off when RNNoise is
active to avoid double-processing. InputGain forced to stereo up-mix to
prevent mono-left-only output from the worklet. Also wires Phase 2 output
device routing (setSinkId) into AppLayout/ChannelSidebar.

packages/web/src/components/layout/AppLayout.tsx

@@ -69,6 +69,14 @@ export function AppLayout() {
     return () => observer.disconnect();
   }, []);
 
+  // Sync persisted output device preference to AudioManager.
+  // AudioManager defers setSinkId until the AudioContext is actually created,
+  // so this is safe to call before any user interaction.
+  const outputDeviceId = useVoiceStore((s) => s.outputDeviceId);
+  useEffect(() => {
+    AudioManager.getInstance().setOutputDevice(outputDeviceId);
+  }, [outputDeviceId]);
+
   const { user, isLoading } = useAuth();
   const setCurrentServer = useServerStore((s) => s.setCurrentServer);
   const loadServerDetail = useServerStore((s) => s.loadServerDetail);