[Feature] support co-design skill

[zengchuang-hw]

• Add co-design skill. Ref: https://gitcode.com/openeuler/yuanrong-datasystem/blob/master/.skills/ds-design/SKILL.md
• Add /imdesign method to invoke co-design skill conveniently

[zengchuang-hw]

I'll test co-design method this week add give a feedback