ui: 优化使用说明弹窗提示文字样式

- 提示文字颜色从 whiteAlpha.400 改为 yellow.300，更醒目
- 字号从 11px 增加到 12px，增加 fontWeight
- 边框颜色调整为金色调

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

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

src/views/Community/components/HeroPanel.js

@@ -751,10 +751,11 @@ const InfoModal = () => {
 
               {/* 操作提示 */}
               <Box
-                pt={2}
+                pt={3}
-                borderTop="1px solid rgba(255,255,255,0.1)"
+                mt={2}
+                borderTop="1px solid rgba(255,215,0,0.2)"
               >
-                <Text fontSize="11px" color="whiteAlpha.400" textAlign="center">
+                <Text fontSize="12px" color="yellow.300" textAlign="center" fontWeight="medium">
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                 </Text>
               </Box>