SkillCheck validator, Cursor exports, and per-agent installers (#27)

Three more learnings from alirezarezvani/claude-skills, applied:

1. SkillCheck validator (scripts/skillcheck.mjs) — validates every SKILL.md
   against the authoring standard (frontmatter, name/folder match, trigger +
   produces clauses, required headings) plus tier referential integrity.
   Errors fail CI; --strict fails on warnings too. New skillcheck.yml workflow
   and a SkillCheck status badge in the README. Current: 0 errors / 14 advisory
   warnings across 172 skills.

2. Cursor export platform — build-exports.mjs now generates
   exports/cursor/<bundle>/<skill>/<skill>.mdc rule files. The PLATFORMS
   registry now supports per-skill filenames (file as a function).

3. Per-agent installers — scripts/install.sh unifies install for
   claude/hermes/codex/openclaw/cursor (--link, --target, --dry-run, --list).
   Curl-able one-liners codex-install.sh, openclaw-install.sh, and
   cursor-install.sh clone the library and install in a single command.

README documents the one-line installs and Cursor exports; CHANGELOG and the
authoring standard updated.


Claude-Session: https://claude.ai/code/session_016JWn5jRD5tcEFKrubjQ6Px

Co-authored-by: Claude <noreply@anthropic.com>

exports/cursor/pm-legal/legal-brief/legal-brief.mdc

@@ -0,0 +1,81 @@
+---
+description: "Draft a structured legal brief, case summary, or legal argument outline. Use when asked to write a legal brief, case note, legal memo, argument outline, or position paper. Produces a structured document using IRAC format (Issue, Rule, Application, Conclusion)."
+globs:
+alwaysApply: false
+---
+
+# Legal Brief Skill
+
+This skill drafts structured legal briefs and memos using IRAC format — the standard structure for legal writing.
+
+## Required Inputs
+- **Brief type** (legal memo / case summary / argument outline / position paper / letter before action)
+- **Legal issue or question**
+- **Jurisdiction** (England & Wales / US / EU / Other)
+- **Relevant facts**
+- **Relevant law or cases** (if known — otherwise flagged as [RESEARCH NEEDED])
+- **Audience** (internal memo / court submission / client letter)
+
+## Output Structure
+
+### Header
+- **To:** [Recipient]
+- **From:** [Author]
+- **Date:** [Date]
+- **Re:** [Matter reference]
+- **Confidential:** Subject to legal professional privilege
+
+### Issue(s)
+One sentence per legal question:
+- Issue 1: Whether X constitutes Y under [law]
+
+### Brief Answer
+One sentence per issue — conclusion upfront before analysis.
+
+### Facts
+Concise relevant facts only. Flag disputed facts.
+
+### Law (Rule)
+- Relevant statute, regulation, or case law
+- How the rule has been interpreted in key cases
+- Flag [RESEARCH NEEDED] where law is not provided
+
+### Application
+- Arguments in favour
+- Counter-arguments and responses
+- Areas of uncertainty flagged explicitly
+
+### Conclusion
+- Clear answer to each issue
+- Overall recommendation
+- Suggested next steps
+
+### Caveats
+What this memo does not cover. What additional research would change the analysis.
+
+---
+
+WARNING: This draft requires review by a qualified legal professional. It does not constitute legal advice.
+
+## Quality Checks
+
+- [ ] Issue is stated as a specific legal question (not a general topic)
+- [ ] Brief answer appears before the analysis (conclusion upfront)
+- [ ] Disputed facts are explicitly flagged
+- [ ] Areas of legal uncertainty are noted (not hidden in confident language)
+- [ ] Caveats section lists what would change the analysis
+- [ ] Disclaimer is included
+
+## Anti-Patterns
+
+- [ ] Do not present uncertain legal positions with confident language — areas of legal ambiguity must be flagged explicitly, not smoothed over
+- [ ] Do not omit the disclaimer — every legal brief output must include the professional review caveat before the user treats it as advice
+- [ ] Do not structure the brief chronologically — IRAC format (Issue, Rule, Application, Conclusion) must be used regardless of how the user framed the request
+- [ ] Do not cite cases or statutes from memory without flagging them as [REQUIRES VERIFICATION] — hallucinated citations are worse than no citations
+- [ ] Do not conflate jurisdiction — legal positions in England & Wales, US, and EU can differ materially; always confirm jurisdiction before stating the rule
+
+## Example Trigger Phrases
+- "Draft a legal memo on [issue]"
+- "Write a legal brief arguing [position]"
+- "Summarise the legal position on [topic]"
+- "Write a letter before action for [situation]"