Optimize skill files for AI agent use with progressive disclosure

- Fix marketplace.json: add 2 missing skills (content-strategy, product-marketing-context)
- Refactor 10 skills over 500 lines to use references/ folders:
  - email-sequence: 926 → 291 lines
  - social-content: 809 → 276 lines
  - competitor-alternatives: 750 → 253 lines
  - pricing-strategy: 712 → 226 lines
  - programmatic-seo: 628 → 235 lines
  - referral-program: 604 → 239 lines
  - schema-markup: 598 → 175 lines
  - free-tool-strategy: 576 → 176 lines
  - paywall-upgrade-cro: 572 → 224 lines
  - marketing-ideas: 566 → 165 lines

Each skill now has core workflow in SKILL.md (<500 lines) with detailed
content in references/ folder for progressive disclosure.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

skills/free-tool-strategy/references/tool-types.md

@@ -0,0 +1,208 @@
+# Free Tool Types Reference
+
+Detailed guide to each type of marketing tool you can build.
+
+## Calculators
+
+**Best for**: Decisions involving numbers, comparisons, estimates
+
+**Examples**:
+- ROI calculator
+- Savings calculator
+- Cost comparison tool
+- Salary calculator
+- Tax estimator
+- Pricing estimator
+- Compound interest calculator
+- Break-even calculator
+
+**Why they work**:
+- Personalized output
+- High perceived value
+- Share-worthy results
+- Clear problem → solution
+
+**Implementation tips**:
+- Keep inputs simple
+- Show calculations transparently
+- Make results shareable
+- Add "powered by" branding
+
+---
+
+## Generators
+
+**Best for**: Creating something useful quickly
+
+**Examples**:
+- Policy generator (privacy, terms)
+- Template generator
+- Name/tagline generator
+- Email subject line generator
+- Resume builder
+- Color palette generator
+- Logo maker
+- Contract generator
+
+**Why they work**:
+- Tangible output
+- Saves time
+- Easily shared
+- Repeat usage
+
+**Implementation tips**:
+- Output should be immediately usable
+- Allow customization
+- Offer download/export options
+- Include email gating for premium outputs
+
+---
+
+## Analyzers/Auditors
+
+**Best for**: Evaluating existing work or assets
+
+**Examples**:
+- Website grader
+- SEO analyzer
+- Email subject tester
+- Headline analyzer
+- Security checker
+- Performance auditor
+- Accessibility checker
+- Code quality analyzer
+
+**Why they work**:
+- Curiosity-driven
+- Personalized insights
+- Creates awareness of problems
+- Natural lead to solution
+
+**Implementation tips**:
+- Score or grade for gamification
+- Benchmark against averages
+- Provide actionable recommendations
+- Follow up with improvement offers
+
+---
+
+## Testers/Validators
+
+**Best for**: Checking if something works
+
+**Examples**:
+- Meta tag preview
+- Email rendering test
+- Mobile-friendly test
+- Speed test
+- DNS checker
+- SSL certificate checker
+- Redirect checker
+- Broken link finder
+
+**Why they work**:
+- Immediate utility
+- Bookmark-worthy
+- Repeat usage
+- Professional necessity
+
+**Implementation tips**:
+- Fast results are essential
+- Show pass/fail clearly
+- Provide fix instructions
+- Integrate with your product where relevant
+
+---
+
+## Libraries/Resources
+
+**Best for**: Reference material
+
+**Examples**:
+- Icon library
+- Template library
+- Code snippet library
+- Example gallery
+- Industry directory
+- Resource list
+- Swipe file collection
+- Font pairing tool
+
+**Why they work**:
+- High SEO value
+- Ongoing traffic
+- Establishes authority
+- Linkable asset
+
+**Implementation tips**:
+- Make searchable/filterable
+- Allow easy copying/downloading
+- Update regularly
+- Accept community submissions
+
+---
+
+## Interactive Educational
+
+**Best for**: Learning/understanding
+
+**Examples**:
+- Interactive tutorials
+- Code playgrounds
+- Visual explainers
+- Quizzes/assessments
+- Simulators
+- Comparison tools
+- Decision trees
+- Configurators
+
+**Why they work**:
+- Engages deeply
+- Demonstrates expertise
+- Shareable
+- Memory-creating
+
+**Implementation tips**:
+- Make it hands-on
+- Show immediate feedback
+- Lead to deeper resources
+- Capture engaged users
+
+---
+
+## Tool Concept Examples by Industry
+
+### SaaS Product
+- Product ROI calculator
+- Competitor comparison tool
+- Readiness assessment quiz
+- Template library for use case
+- Feature configurator
+
+### Agency/Services
+- Industry benchmark tool
+- Project scoping calculator
+- Portfolio review tool
+- Cost estimator
+- Proposal generator
+
+### E-commerce
+- Product finder quiz
+- Comparison tool
+- Size/fit calculator
+- Savings calculator
+- Gift finder
+
+### Developer Tools
+- Code snippet library
+- Testing/preview tool
+- Documentation generator
+- Interactive tutorials
+- API playground
+
+### Finance
+- Financial calculators
+- Investment comparison
+- Budget planner
+- Tax estimator
+- Loan calculator