fix(voice): preserve request ownership across callbacks

keep typed and tool-follow-up responses attached to their original requests
reject duplicate events before they affect newer work
preserve newer input and Radio handoffs during old callback cleanup
integrate the tested main snapshot without dropping existing history

src/voice/realtimeRadio.js

@@ -365,23 +365,23 @@ export class RealtimeRadio {
       epoch: this.radioHandoffEpoch,
       responseId: responseId || null,
     };
+    // Release only the old handoff before abort listeners can create a new one.
+    const shouldStopPlayback = this.radioHandoffInFlight;
+    const attemptId = this.radioHandoffAttemptId;
+    const radioLayer = this.radioLayer;
+    this.pendingRadioPlaybackResult = null;
+    this.radioHandoffInFlightResult = null;
+    this.radioToolHandoffReservations.clear();
+    this.radioHandoffDeferredByReservation = false;
+    this.radioHandoffInFlight = false;
+    this.radioHandoffAttemptId = null;
     if (abortTools) {
       this.abortTools();
     } else if (abortRadioSiblings) {
       this.abortRadioSiblingTools();
     }
-    this.pendingRadioPlaybackResult = null;
-    this.radioHandoffInFlightResult = null;
-    this.radioToolHandoffReservations.clear();
-    this.radioHandoffDeferredByReservation = false;
-    const shouldStopPlayback = this.radioHandoffInFlight;
-    const attemptId = this.radioHandoffAttemptId;
-    // Release ownership before Stop synchronously notifies playback observers;
-    // the resulting callback is then idempotent instead of re-entering Stop.
-    this.radioHandoffInFlight = false;
-    this.radioHandoffAttemptId = null;
     if (shouldStopPlayback) {
-      this.radioLayer?.stopPlayback?.({ origin: 'voice-cleanup', attemptId });
+      radioLayer?.stopPlayback?.({ origin: 'voice-cleanup', attemptId });
     }
   }