Qt does not print default values in --help output; the default passed to the option constructor is only a fallback for value(). Append them to the descriptions instead, via one shared helper used by both programs. Qt 不会把默认值印进 --help(构造参数里的默认值只作为 value() 的兜底), 改为在说明后拼上「(默认 X)」;两个程序共用同一处定义,并统一了措辞。