Add local Codex collage and Xiaohei cat skills

[Pluviobyte]

What changed

• add rn-editorial-collage-motion with editable collage specifications, approved Codex stills, validation, and local FFmpeg or HyperFrames assembly
• add rn-ian-xiaohei-cat-illustrations for recurring-character Xiaohei Cat article illustrations, including character references, composition rules, QA, and calibration examples
• register both Skills in the Claude marketplace and packaging workflow
• update the English and Chinese READMEs with installation, attribution, adaptation, and mixed-license notes
• bump the collection version to 1.2.0

Attribution

The Xiaohei Cat Skill is derived from Ian's original Ian Xiaohei Illustrations, also described as the original Xiaohei Skill. The upstream project is MIT-licensed. The complete Ian copyright notice, source commit 91b560849e8f883922cc2fa8a358a668caa94105, modification summary, and MIT license are retained inside the packaged Skill.

The collage Skill is an independent local adaptation inspired by Vikash Kumar's Arcads Collage Motion Skill. It replaces the Arcads MCP service chain with Codex image generation and local rendering.

Validation

• Skill Creator quick validation: PASS for both new Skills
• marketplace and template JSON validation: PASS
• shell and Python syntax checks: PASS
• packaging test: PASS, including rnskill-1.2.0.zip
• Xiaohei upstream provenance check: all 14 inherited calibration examples match upstream commit 91b560849e8f883922cc2fa8a358a668caa94105
• collage local FFmpeg smoke render: PASS at 1080x1920, 30 fps, H.264