Keep STT listening during TTS playback for interruption detection

- Add sessionActiveRef to track when voice session is active
- Add shouldRestartSTTRef to auto-restart STT after it ends
- STT now continues listening during TTS playback
- Voice detection callback checks both status and isSpeaking
- Final results during TTS are ignored (user interrupted)
- STT automatically restarts after ending if session is still active

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/(tabs)/_layout.tsx

@@ -1,5 +1,5 @@
 import { Tabs } from 'expo-router';
-import React, { useCallback, useEffect } from 'react';
+import React, { useCallback, useEffect, useRef } from 'react';
 import { Platform, View } from 'react-native';
 import { Feather } from '@expo/vector-icons';
 import { useSafeAreaInsets } from 'react-native-safe-area-context';
@@ -22,6 +22,7 @@ export default function TabLayout() {
   // Voice context for listening mode toggle and TTS interruption
   const {
     isListening,
+    isSpeaking,
     status,
     startSession,
     stopSession,
@@ -31,46 +32,95 @@ export default function TabLayout() {
     sendTranscript,
   } = useVoice();
 
+  // Track whether session is active (listening mode on, even during TTS)
+  const sessionActiveRef = useRef(false);
+  // Track if we need to restart STT after it ends during active session
+  const shouldRestartSTTRef = useRef(false);
+
   // Callback for voice detection - interrupt TTS when user speaks
   const handleVoiceDetected = useCallback(() => {
     // Interrupt TTS when user starts speaking during 'speaking' state
-    if (status === 'speaking') {
-      console.log('[TabLayout] Voice detected during speaking - interrupting TTS');
+    if (status === 'speaking' || isSpeaking) {
+      console.log('[TabLayout] Voice detected during TTS playback - interrupting');
       interruptIfSpeaking();
     }
-  }, [status, interruptIfSpeaking]);
+  }, [status, isSpeaking, interruptIfSpeaking]);
+
+  // Callback when STT ends - may need to restart if session is still active
+  const handleSTTEnd = useCallback(() => {
+    console.log('[TabLayout] STT ended, sessionActive:', sessionActiveRef.current);
+    // If session is still active (user didn't stop it), we should restart STT
+    // This ensures STT continues during and after TTS playback
+    if (sessionActiveRef.current) {
+      shouldRestartSTTRef.current = true;
+    }
+  }, []);
 
   // Callback for STT results
   const handleSpeechResult = useCallback((transcript: string, isFinal: boolean) => {
     if (isFinal) {
+      // Only process final results when NOT speaking (avoid processing interrupted speech)
+      if (!isSpeaking && status !== 'speaking') {
         setTranscript(transcript);
         // Send to API when final result is received
         sendTranscript(transcript);
+      } else {
+        // Got final result while speaking - this is the interruption
+        console.log('[TabLayout] Got final result while TTS playing - user interrupted');
+      }
     } else {
       setPartialTranscript(transcript);
     }
-  }, [setTranscript, setPartialTranscript, sendTranscript]);
+  }, [setTranscript, setPartialTranscript, sendTranscript, isSpeaking, status]);
 
   // Speech recognition with voice detection callback
   const {
     startListening,
     stopListening,
+    isListening: sttIsListening,
   } = useSpeechRecognition({
     continuous: true,
     interimResults: true,
     onVoiceDetected: handleVoiceDetected,
     onResult: handleSpeechResult,
+    onEnd: handleSTTEnd,
   });
 
+  // Update session active ref when isListening changes
+  useEffect(() => {
+    sessionActiveRef.current = isListening;
+    if (!isListening) {
+      shouldRestartSTTRef.current = false;
+    }
+  }, [isListening]);
+
   // Start/stop STT when voice session starts/stops
   useEffect(() => {
     if (isListening) {
+      console.log('[TabLayout] Starting STT for voice session');
       startListening();
     } else {
+      console.log('[TabLayout] Stopping STT - session ended');
       stopListening();
     }
   }, [isListening, startListening, stopListening]);
 
+  // Restart STT if it ended while session is still active
+  // This ensures continuous listening even during/after TTS playback
+  useEffect(() => {
+    if (shouldRestartSTTRef.current && sessionActiveRef.current && !sttIsListening) {
+      console.log('[TabLayout] Restarting STT - session still active');
+      shouldRestartSTTRef.current = false;
+      // Small delay to ensure clean restart
+      const timer = setTimeout(() => {
+        if (sessionActiveRef.current) {
+          startListening();
+        }
+      }, 100);
+      return () => clearTimeout(timer);
+    }
+  }, [sttIsListening, startListening]);
+
   // Handle voice FAB press - toggle listening mode
   const handleVoiceFABPress = useCallback(() => {
     if (isListening) {