fix: clean up home top mask measurement

src/pages/index/index.tsx

@@ -90,10 +90,15 @@ export default function Index() {
   }
 
   useEffect(() => {
+    let cancelled = false
+    let measureTimer: ReturnType<typeof setTimeout> | null = null
+
     const measureTitle = () => {
+      if (cancelled) return
       Taro.createSelectorQuery()
         .select('.home-header')
-        .boundingClientRect((rect: { top?: number; bottom?: number; height?: number } | null) => {
+        .boundingClientRect((rect: any) => {
+          if (cancelled) return
           if (!rect || typeof rect.bottom !== 'number' || typeof rect.height !== 'number') {
             const fallbackRange = Math.max(48, safe.headerPaddingTop * 0.45)
             titleMetricsRef.current = {
@@ -113,10 +118,15 @@ export default function Index() {
     }
 
     Taro.nextTick(() => {
-      setTimeout(measureTitle, 80)
+      if (cancelled) return
+      measureTimer = setTimeout(measureTitle, 80)
     })
 
     return () => {
+      cancelled = true
+      if (measureTimer !== null) {
+        clearTimeout(measureTimer)
+      }
       if (scrollFrameRef.current !== null) {
         clearTimeout(scrollFrameRef.current)
       }