fix: 중국어 TTS 끊김 해결 — Chrome pause/resume keepalive

frontend/src/components/korea/OpsGuideModal.tsx

@@ -148,15 +148,26 @@ export function OpsGuideModal({ ships, onClose, onFlyTo, onRouteSelect }: Props)
     window.speechSynthesis.cancel();
     const utter = new SpeechSynthesisUtterance(text);
     utter.lang = 'zh-CN';
-    utter.rate = 0.85;
+    utter.rate = 0.8;
+    utter.pitch = 1.0;
     utter.volume = 1;
-    // Try to find a Chinese voice
     const voices = window.speechSynthesis.getVoices();
-    const zhVoice = voices.find(v => v.lang.startsWith('zh')) || voices.find(v => v.lang.includes('CN'));
+    const zhVoice = voices.find(v => v.lang === 'zh-CN') || voices.find(v => v.lang.startsWith('zh'));
     if (zhVoice) utter.voice = zhVoice;
-    utter.onstart = () => setSpeakingIdx(idx);
-    utter.onend = () => setSpeakingIdx(null);
-    utter.onerror = () => setSpeakingIdx(null);
+    // Chrome bug workaround: pause/resume keepalive to prevent cutoff
+    let keepAlive: ReturnType<typeof setInterval> | null = null;
+    utter.onstart = () => {
+      setSpeakingIdx(idx);
+      keepAlive = setInterval(() => {
+        if (window.speechSynthesis.speaking && !window.speechSynthesis.paused) {
+          window.speechSynthesis.pause();
+          window.speechSynthesis.resume();
+        }
+      }, 5000);
+    };
+    const cleanup = () => { setSpeakingIdx(null); if (keepAlive) clearInterval(keepAlive); };
+    utter.onend = cleanup;
+    utter.onerror = cleanup;
     window.speechSynthesis.speak(utter);
   }, []);