Revert "fix: 将所有emoji/Unicode特殊字符替换为ASCII安全字符"

This reverts commit 3cd67ffe451be2cc7a66b5c554966f1d5aa58c7c.

src/main/java/com/claudecode/tool/impl/GrepTool.java

@@ -164,6 +164,6 @@ public class GrepTool implements Tool {
 
     @Override
     public String activityDescription(Map<String, Object> input) {
-        return "[Grep] '" + input.getOrDefault("pattern", "...") + "'";
+        return "🔍 Searching for '" + input.getOrDefault("pattern", "...") + "'";
     }
 }