domain-skills: add mermaid.live render & validate skill

[MatheusGSD]

Adds domain-skills/mermaid.live/render.md.

What it captures (non-obvious):

• mermaid.live state lives in the URL hash as #pako:<data> where <data> is the editor-state JSON zlib-deflated then URL-safe base64 — plain base64 gives a blank editor. Includes a 6-line Python builder (the harness already runs Python).
• How to confirm a parse/render headlessly (no screenshot, no local mermaid CLI): poll the DOM for an injected svg#graph-* with many <g> nodes vs a syntax-error string. Useful right after editing any file that embeds Mermaid.

Field-tested rendering two diagrams from a docs repo (one with subgraphs + node→subgraph edges + dotted labels; SVG came back with 136 <g> nodes, syntaxErr:false).

🤖 Generated with Claude Code

---

Summary by cubic

Adds a new domain-skills/mermaid.live/render.md skill that explains how to render and validate Mermaid diagrams in mermaid.live via the #pako: URL hash. Enables headless parse checks without screenshots or the Mermaid CLI.

• New Features
  • Documents the #pako: hash format for mermaid.live (zlib-deflated, URL-safe base64 editor state JSON; plain base64 yields a blank editor).
  • Includes a small Python helper to build the URL and notes a short post-load wait for client-side render.
  • Describes a DOM-based check to confirm parse success (look for svg#graph-* with many <g> nodes or detect syntax error text).

^{Written for commit 51f0075. Summary will update on new commits.}

[browser-harness-review]

✅ Skill review passed

Reviewed 1 file(s) — no findings.

[cubic-dev-ai]

No issues found across 1 file

_{Re-trigger cubic}