Add SKILL for airflowctl command development

[bugraoz93]

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Was generative AI tooling used to co-author this PR?

• Yes (please specify the tool below)
  Claude Opus 4.7

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[potiuk]

I don;'t think SKILLS are usable in monorepo structure this way. SKILLS should I think be placed in .gihub/skills and linked from .claude/skills to take effect (BTW we should likely just link the whole skills folder not individual skills - I will doi it in a moment.