fix(play): resolve hydration mismatch and fragile pace index

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/page.tsx

@@ -1261,6 +1261,7 @@ export default function HomePage() {
 
   const styleRow = OPTS.findIndex((o) => o.modal);
   const voiceRow = OPTS.findIndex((o) => o.label === "语音配音");
+  const paceRow = OPTS.findIndex((o) => o.label === "内容节奏");
   const genderIndex = sel[0] ?? 0;
   const gender = (OPTS[0]!.items[genderIndex] as Gender) ?? "男性向";
   const phrases = EXAMPLE_PHRASES[gender];
@@ -1335,7 +1336,7 @@ export default function HomePage() {
     const plotStyle = PLOT_STYLES[sel[2] ?? 1] ?? "多线转折";
     const voice = OPTS[voiceRow]!.items[sel[voiceRow] ?? 1]!;
     const audioEnabled = voice === "开启";
-    const pace = PACINGS[sel[4] ?? 1] ?? "紧凑爽快";
+    const pace = PACINGS[sel[paceRow] ?? 1] ?? "紧凑爽快";
 
     // worldSetting 顺序很重要：玩家输入若存在，必须放在最前面、单独成段、
     // 用强指令包住，否则模型会把它当成夹在风格说明里的背景参考、扩写出

app/play/page.tsx

@@ -580,10 +580,7 @@ function PlayInner() {
   // Once the player dismisses the silence nudge, keep it gone for this session.
   const [nudgeDismissed, setNudgeDismissed] = useState(false);
   const [settingsOpen, setSettingsOpen] = useState(false);
-  const [visionClickEnabled, setVisionClickEnabled] = useState<boolean>(() => {
-    if (typeof window === "undefined") return true;
-    return readStoredVisionClick();
-  });
+  const [visionClickEnabled, setVisionClickEnabled] = useState(true);
 
   const startedRef = useRef(false);
   const poolRef = useRef<Map<string, PrefetchEntry>>(new Map());
@@ -653,6 +650,9 @@ function PlayInner() {
   useEffect(() => {
     mutedRef.current = muted;
   }, [muted]);
+  useEffect(() => {
+    setVisionClickEnabled(readStoredVisionClick());
+  }, []);
 
   // Coarse liveness ping for active-time analytics. /play is a single SPA
   // route, so page views alone read as ~0 duration; a 30s heartbeat (only