修复积分弹窗列表滚动穿透及优化加载更多

- 通过`nestedScroll`修复`LazyColumn`在`ModalBottomSheet`中滚动时导致底部工作表（BottomSheet）也跟着滚动的问题。
- 移除手动点击的“加载更多”按钮，改为滚动到底部时自动加载更多积分记录。
- 引入`debounce`和`distinctUntilChanged`来优化滚动加载逻辑，防止重复触发。
- 在积分列表底部添加了“加载中”和“已经到底”的提示文本。
- 调整了Tab项的布局，使用`SpaceBetween`使其均匀分布。

app/src/main/java/com/aiosman/ravenow/ui/points/PointsBottomSheet.kt

@@ -13,7 +13,9 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.clickable
@@ -30,8 +32,16 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
+import androidx.compose.runtime.snapshotFlow
 import androidx.compose.ui.Alignment
+import kotlinx.coroutines.flow.debounce
+import kotlinx.coroutines.flow.distinctUntilChanged
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.input.nestedscroll.NestedScrollConnection
+import androidx.compose.ui.input.nestedscroll.nestedScroll
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.input.nestedscroll.NestedScrollSource
+import androidx.compose.ui.unit.Velocity
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.res.painterResource
@@ -71,10 +81,15 @@ fun PointsBottomSheet(
         sheetState = sheetState,
         containerColor = AppColors.background
     ) {
-        Column(
+        Box(
             modifier = Modifier
                 .fillMaxWidth()
                 .fillMaxHeight(0.9f)
+        ) {
+            Column(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .fillMaxHeight()
                     .padding(horizontal = 16.dp, vertical = 8.dp)
             ) {
             // 头部
@@ -156,7 +171,7 @@ fun PointsBottomSheet(
                 modifier = Modifier
                     .fillMaxWidth()
                     .padding(horizontal = 16.dp),
-                horizontalArrangement = Arrangement.Start,
+                horizontalArrangement = Arrangement.SpaceBetween,
                 verticalAlignment = Alignment.CenterVertically
             ) {
                 TabItem(
@@ -165,7 +180,6 @@ fun PointsBottomSheet(
                     onClick = { tab = 0 },
                     modifier = Modifier.weight(1f)
                 )
-                TabSpacer()
                 TabItem(
                     text = stringResource(R.string.how_to_earn),
                     isSelected = tab == 1,
@@ -189,6 +203,7 @@ fun PointsBottomSheet(
             }
         }
     }
+}
 
 @Composable
 private fun SegmentItem(selected: Boolean, text: String, onClick: () -> Unit) {
@@ -211,9 +226,75 @@ private fun PointsHistoryList(
 ) {
     val AppColors = LocalAppTheme.current
     val numberFormat = remember { NumberFormat.getNumberInstance(Locale.getDefault()) }
+    val listState = rememberLazyListState()
+    val loading = PointsViewModel.loading
+    var lastLoadTriggeredIndex by remember { mutableStateOf(-1) }
+    var previousItemsSize by remember { mutableStateOf(items.size) }
+
+    // 创建 NestedScrollConnection 来阻止滚动事件向上传播到 ModalBottomSheet
+    // 使用 onPostScroll 来消费 LazyColumn 处理后的剩余滚动事件
+    val nestedScrollConnection = remember {
+        object : NestedScrollConnection {
+            override fun onPreScroll(available: Offset, source: NestedScrollSource): Offset {
+                // 不消费任何事件，让 LazyColumn 先处理
+                return Offset.Zero
+            }
+
+            override fun onPostScroll(consumed: Offset, available: Offset, source: NestedScrollSource): Offset {
+                // 消费 LazyColumn 处理后的剩余滚动事件，防止传递到 ModalBottomSheet
+                return available
+            }
+
+            override suspend fun onPreFling(available: Velocity): Velocity {
+                // 不消费惯性滚动，让 LazyColumn 先处理
+                return Velocity.Zero
+            }
+
+            override suspend fun onPostFling(consumed: Velocity, available: Velocity): Velocity {
+                // 消费 LazyColumn 处理后的剩余惯性滚动，防止传递到 ModalBottomSheet
+                return available
+            }
+        }
+    }
+
+    // 当数据加载完成后，重置触发索引，以便可以继续加载
+    LaunchedEffect(items.size, loading) {
+        if (items.size > previousItemsSize && !loading) {
+            // 数据已加载完成，重置触发索引
+            lastLoadTriggeredIndex = -1
+            previousItemsSize = items.size
+        } else if (items.size != previousItemsSize) {
+            previousItemsSize = items.size
+        }
+    }
+
+    // 监听滚动位置，接近底部时自动加载更多
+    LaunchedEffect(Unit) {
+        snapshotFlow { 
+            listState.layoutInfo.visibleItemsInfo.lastOrNull()?.index ?: -1
+        }
+            .debounce(500) // 防抖500ms，等待滚动停止后再触发，避免快速滚动时频繁触发
+            .distinctUntilChanged() // 只在值变化时触发
+            .collect { lastVisibleIndex ->
+                if (lastVisibleIndex >= 0 && hasNext && !loading) {
+                    val totalItems = items.size
+                    // 当滚动到倒数第3个item时，触发加载更多
+                    // 并且确保不会重复触发（检查上次触发的索引）
+                    if (totalItems > 0 && 
+                        lastVisibleIndex >= totalItems - 3 && 
+                        lastVisibleIndex != lastLoadTriggeredIndex) {
+                        lastLoadTriggeredIndex = lastVisibleIndex
+                        onLoadMore()
+                    }
+                }
+            }
+    }
 
     LazyColumn(
-        modifier = Modifier.fillMaxWidth()
+        state = listState,
+        modifier = Modifier
+            .fillMaxWidth()
+            .nestedScroll(nestedScrollConnection)
     ) {
         items(items) { item ->
             Row(
@@ -249,12 +330,37 @@ private fun PointsHistoryList(
                 )
             }
         }
-        if (hasNext) {
+        // 显示加载状态
+        if (loading && items.isNotEmpty()) {
             item {
-                Button(onClick = onLoadMore, modifier = Modifier
+                Box(
+                    modifier = Modifier
                         .fillMaxWidth()
-                    .padding(top = 8.dp)) {
-                    Text(stringResource(R.string.load_more))
+                        .padding(16.dp),
+                    contentAlignment = Alignment.Center
+                ) {
+                    Text(
+                        text = stringResource(R.string.load_more),
+                        color = AppColors.secondaryText,
+                        fontSize = 14.sp
+                    )
+                }
+            }
+        }
+        // 显示已经到底提示
+        if (!hasNext && items.isNotEmpty()) {
+            item {
+                Box(
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .padding(16.dp),
+                    contentAlignment = Alignment.Center
+                ) {
+                    Text(
+                        text = "已经到底",
+                        color = AppColors.secondaryText,
+                        fontSize = 14.sp
+                    )
                 }
             }
         }
@@ -265,6 +371,31 @@ private fun PointsHistoryList(
 private fun HowToEarnList() {
     val AppColors = LocalAppTheme.current
 
+    // 创建 NestedScrollConnection 来阻止滚动事件向上传播到 ModalBottomSheet
+    val nestedScrollConnection = remember {
+        object : NestedScrollConnection {
+            override fun onPreScroll(available: Offset, source: NestedScrollSource): Offset {
+                // 不消费任何事件，让 LazyColumn 先处理
+                return Offset.Zero
+            }
+
+            override fun onPostScroll(consumed: Offset, available: Offset, source: NestedScrollSource): Offset {
+                // 消费 LazyColumn 处理后的剩余滚动事件，防止传递到 ModalBottomSheet
+                return available
+            }
+
+            override suspend fun onPreFling(available: Velocity): Velocity {
+                // 不消费惯性滚动，让 LazyColumn 先处理
+                return Velocity.Zero
+            }
+
+            override suspend fun onPostFling(consumed: Velocity, available: Velocity): Velocity {
+                // 消费 LazyColumn 处理后的剩余惯性滚动，防止传递到 ModalBottomSheet
+                return available
+            }
+        }
+    }
+
     @Composable
     fun RowItem(title: String, desc: String, amount: String) {
         Row(
@@ -294,7 +425,9 @@ private fun HowToEarnList() {
     }
 
     LazyColumn(
-        modifier = Modifier.fillMaxWidth()
+        modifier = Modifier
+            .fillMaxWidth()
+            .nestedScroll(nestedScrollConnection)
     ) {
         item {
             RowItem(stringResource(R.string.new_user_reward), stringResource(R.string.new_user_reward_desc), "+500")