Add Mermaid research diagram skill

[vikvang]

Summary

• Add a mermaid-research-diagram skill for turning research papers, technical blogs, AI writeups, architecture posts, benchmarks, and pasted excerpts into Mermaid diagrams.
• Include workflow guidance for selecting diagram types, preserving uncertainty, and keeping diagrams source-faithful.
• Cover tweet-friendly diagrams plus AI-agent/context-engineering caveats such as compaction, KV cache pressure, and noisy trajectories.

Testing

• Ran a local metadata validation script checking frontmatter, directory/name match, license: MIT, Use when... trigger sentence, and single-H1 structure.

Co-Authored-By: Oz oz-agent@warp.dev