style(GlobalSidebar): 优化收起状态文字样式

- 字体大小从 10px 调整为 xs (12px)
- 文字亮度从 0.5/0.6 提升到 0.8/0.85
- 添加 fontWeight="medium" 加粗显示

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/components/GlobalSidebar/index.js

@@ -55,8 +55,8 @@ const CollapsedMenu = ({
     <VStack spacing={4} py={4} align="center">
       {/* 展开按钮 */}
       <HStack spacing={1} w="100%" justify="center" cursor="pointer" onClick={onToggle} _hover={{ bg: 'rgba(255, 255, 255, 0.05)' }} py={1} borderRadius="md">
-        <Icon as={ChevronLeft} boxSize={4} color="rgba(255, 255, 255, 0.6)" />
-        <Text fontSize="10px" color="rgba(255, 255, 255, 0.5)">
+        <Icon as={ChevronLeft} boxSize={4} color="rgba(255, 255, 255, 0.8)" />
+        <Text fontSize="xs" color="rgba(255, 255, 255, 0.8)" fontWeight="medium">
           展开
         </Text>
       </HStack>
@@ -93,7 +93,7 @@ const CollapsedMenu = ({
                 </Badge>
               )}
             </Box>
-            <Text fontSize="10px" color="rgba(255, 255, 255, 0.6)" whiteSpace="nowrap">
+            <Text fontSize="xs" color="rgba(255, 255, 255, 0.85)" fontWeight="medium" whiteSpace="nowrap">
               关注股票
             </Text>
           </VStack>
@@ -165,7 +165,7 @@ const CollapsedMenu = ({
                 </Badge>
               )}
             </Box>
-            <Text fontSize="10px" color="rgba(255, 255, 255, 0.6)" whiteSpace="nowrap">
+            <Text fontSize="xs" color="rgba(255, 255, 255, 0.85)" fontWeight="medium" whiteSpace="nowrap">
               关注事件
             </Text>
           </VStack>
@@ -219,7 +219,7 @@ const CollapsedMenu = ({
             position="relative"
           >
             <Icon as={TrendingUp} boxSize={5} color="rgba(34, 197, 94, 0.9)" />
-            <Text fontSize="10px" color="rgba(255, 255, 255, 0.6)" whiteSpace="nowrap">
+            <Text fontSize="xs" color="rgba(255, 255, 255, 0.85)" fontWeight="medium" whiteSpace="nowrap">
               热门板块
             </Text>
           </VStack>