Add Modellix skill for AI image and video generation

[alen-hh]

Summary

• Add English skill listing at src/content/skills/modellix.md
• Add Chinese translation at src/content/skills-zh/modellix.md (slug-linked)
• Points to the public package: https://github.com/Modellix/modellix-skill/tree/main/modellix-skill

Why

Modellix provides a unified API/CLI for async AI image and video generation. Listing it helps Qoder users discover CLI-first workflows (doctor → model run --wait → task download).

Install (for reviewers)

git clone https://github.com/Modellix/modellix-skill
cp -r modellix-skill/modellix-skill ~/.qoder/skills/modellix
npm i -g modellix-cli@latest

Checklist

• Follows CONTRIBUTING skill template frontmatter
• EN + ZH content
• One skill per PR
• npm run build (content-only change; please run in CI if required)

Made with Cursor

[alen-hh]

Refreshed this PR: the upstream repository was renamed from Modellix/modellix-skill to Modellix/modellix-plugin and the skill now ships at skills/modellix. Updated githubUrl, docsUrl, installCommand, lastUpdated, and the install notes in both the EN and ZH content files. Content-only change.