Add multi-platform export generator (single source of truth)

Make the library multi-platform without duplicating content. Each
skills/<name>/SKILL.md body remains the single source of truth; a new
generator renders platform-ready exports from it.

- scripts/build-exports.mjs — dependency-free Node generator with a PLATFORMS
  registry so new platforms (Gemini, Cursor, …) are a few lines. Ships ChatGPT
  exports at exports/chatgpt/<bundle>/<skill>/SYSTEM_PROMPT.md (172 skills),
  plus generated index READMEs. Supports --platform and --check.
- exports/ — generated ChatGPT system prompts, ready to paste into a Custom GPT.
- .github/workflows/check-generated.yml — fails a PR if exports or
  web/skills.json drift from the source skills.
- README "Works With" now documents the ready-to-use exports and regen command.
- CHANGELOG + SKILL-AUTHORING-STANDARD note the generated artifacts.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016JWn5jRD5tcEFKrubjQ6Px

exports/chatgpt/pm-legal/nda-analyser/SYSTEM_PROMPT.md

@@ -0,0 +1,71 @@
+# NDA Analyser Skill
+
+NDAs are often treated as routine paperwork but contain terms with significant long-term consequences. This skill analyses them systematically.
+
+## Required Inputs
+- **NDA text** (paste in full or describe key clauses)
+- **Your party position** (disclosing / receiving / mutual)
+- **Purpose of the NDA** (e.g. pre-sales, hiring, M&A, partnership)
+- **Industry context** (optional)
+
+## Output Structure
+
+### 1. NDA Type and Parties
+- **Type:** Unilateral / Mutual
+- **Disclosing party:** [Name]
+- **Receiving party:** [Name]
+- **Purpose:** [As stated]
+- **Governing law:** [Jurisdiction]
+- **Term:** [Duration of obligations]
+
+### 2. Definition of Confidential Information
+- **How broadly defined?** Narrow / Standard / Very broad
+- **Oral disclosures included?** Yes / No / With conditions
+- **Standard exclusions present?** [public domain, prior knowledge, independently developed, legally required disclosure]
+- **Flag:** [Unusual inclusions or missing exclusions]
+
+### 3. Key Clause Analysis
+
+**[Clause name] — Concern / Watch / Standard**
+- **What it says:** [Plain English]
+- **Issue:** [Why flagged]
+- **Standard position:** [What this typically looks like]
+- **Negotiation suggestion:** [If applicable]
+
+Clauses always covered: permitted use, non-solicitation/non-compete, term and post-termination obligations, return/destruction of information, remedies, liability, residuals clause.
+
+### 4. Negotiation Checklist
+
+| Point | Current position | Suggested ask |
+|---|---|---|
+| [e.g. Confidentiality term] | [e.g. 5 years] | [e.g. Reduce to 2 years] |
+
+### 5. Plain English Verdict
+2-3 sentences. Standard NDA, one-sided, or needs a lawyer?
+
+---
+
+WARNING: This analysis is for informational purposes only and is not legal advice. Consult a qualified solicitor before signing.
+
+## Quality Checks
+
+- [ ] Definition of confidential information assessed for scope (narrow / standard / very broad)
+- [ ] Residuals clause checked (allows memory use of disclosed information — high-risk)
+- [ ] Non-solicitation / non-compete provisions flagged
+- [ ] Post-termination obligations duration noted
+- [ ] Plain English verdict given (standard / one-sided / needs lawyer)
+- [ ] Disclaimer is included
+
+## Anti-Patterns
+
+- [ ] Do not present the analysis as legal advice — the disclaimer must appear prominently and the output must recommend qualified legal review before any signing decision
+- [ ] Do not skip the residuals clause check — residuals clauses allow the receiving party to use disclosed information from memory, which is one of the highest-risk provisions in any NDA
+- [ ] Do not evaluate only the clauses explicitly flagged by the user — a complete analysis must cover all standard clause types even if the user only asked about one
+- [ ] Do not assess breadth of the confidentiality definition without checking for oral disclosure coverage — oral disclosures with no written confirmation requirement are a common enforcement gap
+- [ ] Do not omit the plain English verdict — a clause-by-clause analysis without a summary conclusion leaves the user unable to act on the findings
+
+## Example Trigger Phrases
+- "Analyse this NDA"
+- "Review this confidentiality agreement"
+- "Is this NDA standard or unusual?"
+- "What should I negotiate in this mutual NDA?"