refactor(h-hosts-docker.sh): 优化配置更新检测逻辑

- 修改了 diff 命令的使用方式，将输出重定向到 /dev/null
- 仅在配置发生变化时显示变更详情
- 优化了脚本的逻辑结构，提高了可读性和效率

h-hosts-docker.sh

@@ -75,12 +75,12 @@ echo "$updated_json" > "$DAEMON_FILE"
 
 # 6. 显示修改前后的差异
 echo "🔄  检查文件变更:"
-diff -u "$BACKUP_FILE" "$DAEMON_FILE"
-
-if [ $? -eq 0 ]; then
+if diff -u "$BACKUP_FILE" "$DAEMON_FILE" > /dev/null; then
     echo "✅  配置未发生变化，所有条目均已存在。"
 else
     echo "✅  成功更新 '$DAEMON_FILE'！"
+    echo "变更详情:"
+    diff -u "$BACKUP_FILE" "$DAEMON_FILE"
 fi
 
 # -- 完成 --