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-sales/sales-battlecard/sales-battlecard.mdc

@@ -0,0 +1,97 @@
+---
+description: "Create a competitive sales battlecard for any competitor. Use when asked to build a battlecard, competitive comparison, sales cheat sheet, or objection handling guide for a specific competitor. Produces a one-page battlecard with positioning, differentiators, objection responses, and landmines."
+globs:
+alwaysApply: false
+---
+
+# Sales Battlecard Skill
+
+Produces a practical one-page competitive battlecard that sales reps can use in calls — not a theoretical analysis.
+
+## Required Inputs
+- **Your product/company**
+- **Competitor name**
+- **Your target customer** (ICP)
+- **Your top 3 differentiators** vs this competitor
+- **Common objections** when competing against them
+- **Known competitor weaknesses**
+
+## Output Structure
+
+---
+
+# Battlecard: [Your Product] vs [Competitor]
+Updated: [Date] — Review quarterly
+
+---
+
+### In One Sentence
+When a prospect mentions [Competitor], say: "[Your positioning in one sentence]"
+
+---
+
+### Why Customers Choose [Competitor]
+(Be honest about their genuine strengths)
+- [Strength 1]
+- [Strength 2]
+
+---
+
+### Why Customers Choose Us
+(Specific differentiators with proof points)
+- **[Differentiator 1]:** [Proof point — customer outcome or capability]
+- **[Differentiator 2]:** [Proof point]
+
+---
+
+### Objection Responses
+
+**"[Competitor] is cheaper"**
+"You are right their list price is lower. What our customers find is [specific TCO difference]. [Customer] saw [result]. Should we explore total cost of ownership?"
+
+**"We already use [Competitor]"**
+"That is helpful. What is working well? [Listen] And what is one thing you wish was better?"
+
+**"[Competitor] has [feature] you do not"**
+"You are right. What problem are you solving with that feature? [Listen] Here is how our customers solve that..."
+
+---
+
+### Landmines to Plant
+- "How do you currently handle [area where competitor is weak]?"
+- "What happens when you need to [scenario competitor struggles with]?"
+
+---
+
+### Traps to Avoid
+- Never badmouth [Competitor] directly
+- Do not lead with features — lead with the prospect problem
+- Do not claim you do everything better — be specific about where you win
+
+---
+
+### When We Win / When We Lose
+We win when: [Scenario — e.g. customer prioritises outcome over price]
+We lose when: [Honest scenario — e.g. primary driver is lowest upfront cost]
+
+## Quality Checks
+
+- [ ] Competitor strengths are listed honestly (not minimised)
+- [ ] Differentiators have proof points (not just claims)
+- [ ] Objection responses are conversational (not scripted-sounding)
+- [ ] Landmine questions are natural and non-confrontational
+- [ ] "When we lose" is included and honest
+- [ ] Battlecard has a review date
+
+## Example Trigger Phrases
+- "Build a battlecard against [competitor]"
+- "Create a competitive cheat sheet for [competitor]"
+- "Write objection handling for [competitor] comparisons"
+
+## Anti-Patterns
+
+- [ ] Do not minimise or ignore genuine competitor strengths — sales reps who encounter them unprepared lose credibility
+- [ ] Do not write differentiators without proof points — a claim without evidence is marketing, not a battlecard
+- [ ] Do not make the battlecard exhaustive — it is a one-page cheat sheet, not a full competitive analysis
+- [ ] Do not include a "When we lose" section that is dishonestly optimistic — honest loss scenarios build rep trust
+- [ ] Do not skip the review date — an outdated battlecard with wrong information is worse than no battlecard