skill: create `add-new-model` and `code-review` (#26042)
* skill: add new model
* add common pitfalls
* add code review skill
* nits
* add codeowners
* add security review section
* mention about skills in agents.md
* add design review
* exclude ggml-gh-bot
* Apply suggestions from code review
Co-authored-by: Piotr Wilkin (ilintar) <piotr.wilkin@syndatis.com>
Co-authored-by: Xuan-Son Nguyen <thichthat@gmail.com>
* conversion-time weight modification
* nits
---------
Co-authored-by: Piotr Wilkin (ilintar) <piotr.wilkin@syndatis.com>
