feat(bash): 优化输出截断逻辑，确保处理UTF-8字符边界

src/tools/bash.rs

@@ -61,16 +61,22 @@ impl BashTool {
     }
 
     fn truncate_output(&self, output: &str) -> String {
-        if output.len() <= MAX_OUTPUT_CHARS {
+        let char_count = output.chars().count();
+        if char_count <= MAX_OUTPUT_CHARS {
             return output.to_string();
         }
 
         let half = MAX_OUTPUT_CHARS / 2;
+        let head: String = output.chars().take(half).collect();
+        let tail: String = output
+            .chars()
+            .skip(char_count.saturating_sub(half))
+            .collect();
         format!(
             "{}...\n\n(... {} chars truncated ...)\n\n{}",
-            &output[..half],
+            head,
-            output.len() - MAX_OUTPUT_CHARS,
+            char_count - MAX_OUTPUT_CHARS,
-            &output[output.len() - half..]
+            tail
         )
     }
 }
@@ -312,4 +318,15 @@ mod tests {
         assert!(!result.success);
         assert!(result.error.unwrap().contains("timed out"));
     }
+
+    #[test]
+    fn test_truncate_output_handles_utf8_char_boundaries() {
+        let tool = BashTool::new();
+        let input = "全".repeat(MAX_OUTPUT_CHARS + 100);
+
+        let output = tool.truncate_output(&input);
+
+        assert!(output.contains("chars truncated"));
+        assert!(output.is_char_boundary(output.len()));
+    }
 }