refactor(call): move noise-suppression toggle out of the call bar

Default flipped to off so voice doesn't get coloured by browser NS on
first run. Users turn it on explicitly under Settings → Sprache, where
the toggle already lived before the in-call button shipped.

The in-call SparklesIcon button and all the associated wiring
(onToggleNoiseSuppression, noiseSuppression prop, local subscription
in InCallPanel) is removed. The hot-swap UX is preserved: a new
subscribeAudioSettings watcher in CallContext detects noiseSuppression
flips during an active call and re-runs setupMicPipeline so the change
takes effect without rejoining.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/desktop/src/context/CallContext.tsx

@@ -1235,6 +1235,23 @@ export function CallProvider({ children }: { children: ReactNode }) {
     });
   }, []);
 
+  // Hot-swap the mic track when the user flips noiseSuppression in Settings
+  // so the change takes effect without needing to rejoin the call. Tracks
+  // the previous value in a ref so we only re-acquire getUserMedia on
+  // actual transitions (avoid a rebuild on every unrelated settings save).
+  useEffect(() => {
+    let lastNs = getAudioSettings().noiseSuppression;
+    return subscribeAudioSettings((s) => {
+      if (s.noiseSuppression === lastNs) return;
+      lastNs = s.noiseSuppression;
+      const r = roomRef.current;
+      if (!r) return;
+      // setupMicPipeline re-reads audioSettings so the new NS constraint
+      // gets picked up. Same helper as the initial join + retry paths.
+      void setupMicPipeline(r);
+    });
+  }, [setupMicPipeline]);
+
   // --- Push-to-talk ------------------------------------------------------
   // While PTT is active + we're in a connected call, the mic is held off
   // except while the configured key is pressed. Under Tauri we also register