perf(custom): sppage锁定屏幕导致抖动问题

src/components/sp-page/index.js

@@ -85,18 +85,28 @@ const SpPage = memo(
 
     useEffect(() => {
       if (state.lock) {
+        // 保存当前滚动位置
+        const currentScrollTop = scrollTopRef.current || 0
+        
         setState((draft) => {
           draft.lockStyle = {
-            position: 'fixed',
-            top: `-${scrollTopRef.current}px`,
-            left: '0px',
-            width: '100%',
-            bottom: '0px'
+            overflow: 'hidden'
           }
         })
+        
+        // 设置滚动位置，防止回到顶部
+        setTimeout(() => {
+          Taro.pageScrollTo({
+            scrollTop: currentScrollTop,
+            duration: 0
+          })
+        }, 0)
+        
       } else {
         setState((draft) => {
-          draft.lockStyle = {}
+          draft.lockStyle = {
+            overflow: 'auto'
+          }
         })
       }
     }, [state.lock])
@@ -260,13 +270,6 @@ const SpPage = memo(
         setState((draft) => {
           draft.lock = false
         })
-
-        setTimeout(() => {
-          Taro.pageScrollTo({
-            scrollTop: scrollTopRef.current,
-            duration: 0
-          })
-        }, 0)
       }
     }))
     const computedNavigationStyle = () => {