refactor: 提取翻页按钮为可复用组件

- 创建 PageNavigationButton 组件
  · 通过 direction 参数区分上一页/下一页
  · 内置主题适配和模式判断逻辑
  · 自动处理显示条件（只在单排/双排模式显示）

- 重构 EventScrollList
  · 删除重复的翻页按钮代码（减少 66 行）
  · 使用 PageNavigationButton 组件替换原有按钮
  · 移除未使用的导入（IconButton, ChevronLeftIcon, ChevronRightIcon）
  · 移除翻页按钮主题色定义（已移至子组件）

优点：
- 消除重复代码，提升可维护性
- 职责分离，逻辑更清晰
- 易于扩展（可添加首页/末页按钮）

src/views/Community/components/DynamicNewsCard/EventScrollList.js

@@ -7,7 +7,6 @@ import {
   Flex,
   Grid,
   GridItem,
-  IconButton,
   Button,
   ButtonGroup,
   Center,
@@ -17,13 +16,13 @@ import {
   Text,
   useColorModeValue
 } from '@chakra-ui/react';
-import { ChevronLeftIcon, ChevronRightIcon } from '@chakra-ui/icons';
 import DynamicNewsEventCard from '../EventCard/DynamicNewsEventCard';
 import CompactEventCard from '../EventCard/CompactEventCard';
 import HorizontalDynamicNewsEventCard from '../EventCard/HorizontalDynamicNewsEventCard';
 import DynamicNewsDetailPanel from '../DynamicNewsDetail';
 import PaginationControl from './PaginationControl';
 import VirtualizedFourRowGrid from './VirtualizedFourRowGrid';
+import PageNavigationButton from './PageNavigationButton';
 
 /**
  * 事件列表组件 - 支持两种展示模式
@@ -68,10 +67,6 @@ const EventScrollList = ({
   const timelineBorderColor = useColorModeValue('gray.400', 'gray.500');
   const timelineTextColor = useColorModeValue('blue.600', 'blue.400');
 
-  // 翻页按钮颜色
-  const arrowBtnBg = useColorModeValue('rgba(255, 255, 255, 0.9)', 'rgba(0, 0, 0, 0.6)');
-  const arrowBtnHoverBg = useColorModeValue('rgba(255, 255, 255, 1)', 'rgba(0, 0, 0, 0.8)');
-
   // 滚动条颜色
   const scrollbarTrackBg = useColorModeValue('#f1f1f1', '#2D3748');
   const scrollbarThumbBg = useColorModeValue('#888', '#4A5568');
@@ -140,68 +135,21 @@ const EventScrollList = ({
       {/* 横向滚动区域 */}
       <Box position="relative">
 
-        {/* 左侧翻页按钮 - 上一页 */}
-      {currentPage > 1 && (
-        <IconButton
-          icon={<ChevronLeftIcon boxSize={6} color="blue.500" />}
-          position="absolute"
-          left="0"
-          top="50%"
-          transform="translateY(-50%)"
-          zIndex={2}
-          onClick={() => {
-            console.log(`%c🔵 [翻页] 点击上一页: 当前页${currentPage} → 目标页${currentPage - 1} (共${totalPages}页)`, 'color: #3B82F6; font-weight: bold;');
-            onPageChange(currentPage - 1);
-          }}
-          variant="ghost"
-          size="md"
-          w="40px"
-          h="40px"
-          minW="40px"
-          borderRadius="full"
-          bg={arrowBtnBg}
-          boxShadow="0 2px 8px rgba(0, 0, 0, 0.15)"
-          _hover={{
-            bg: arrowBtnHoverBg,
-            boxShadow: '0 4px 12px rgba(0, 0, 0, 0.2)',
-            transform: 'translateY(-50%) scale(1.05)'
-          }}
-          aria-label="上一页"
-          title="上一页"
+        {/* 翻页导航按钮 */}
+        <PageNavigationButton
+          direction="prev"
+          currentPage={currentPage}
+          totalPages={totalPages}
+          onPageChange={onPageChange}
+          mode={mode}
         />
-      )}
-
-      {/* 右侧翻页按钮 - 下一页 */}
-      {currentPage < totalPages && (
-        <IconButton
-          icon={<ChevronRightIcon boxSize={6} color="blue.500" />}
-          position="absolute"
-          right="0"
-          top="50%"
-          transform="translateY(-50%)"
-          zIndex={2}
-          onClick={() => {
-            console.log(`%c🔵 [翻页] 点击下一页: 当前页${currentPage} → 目标页${currentPage + 1} (共${totalPages}页)`, 'color: #3B82F6; font-weight: bold;');
-            onPageChange(currentPage + 1);
-          }}
-          variant="ghost"
-          size="md"
-          w="40px"
-          h="40px"
-          minW="40px"
-          borderRadius="full"
-          bg={arrowBtnBg}
-          boxShadow="0 2px 8px rgba(0, 0, 0, 0.15)"
-          _hover={{
-            bg: arrowBtnHoverBg,
-            boxShadow: '0 4px 12px rgba(0, 0, 0, 0.2)',
-            transform: 'translateY(-50%) scale(1.05)'
-          }}
-          isDisabled={currentPage >= totalPages}
-          aria-label="下一页"
-          title="下一页"
+        <PageNavigationButton
+          direction="next"
+          currentPage={currentPage}
+          totalPages={totalPages}
+          onPageChange={onPageChange}
+          mode={mode}
         />
-      )}
 
       {/* 事件卡片容器 */}
       <Box