Add experiment ideas sections to all CRO skills

Adds curated A/B test experiments from SaaS CRO playbook to:
- page-cro: homepage, pricing, demo, resource page experiments
- signup-flow-cro: form design, copy, trial, post-submit experiments
- onboarding-cro: flow simplification, guided experience, personalization
- form-cro: structure, copy, mobile, type-specific experiments
- popup-cro: placement, triggers, messaging, personalization
- paywall-upgrade-cro: triggers, design, pricing, trials, personalization

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

skills/form-cro.md

@@ -325,6 +325,86 @@ Ideas to A/B test with expected outcomes
 
 ---
 
+## Experiment Ideas
+
+### Form Structure Experiments
+
+**Layout & Flow**
+- Single-step form vs. multi-step with progress bar
+- 1-column vs. 2-column field layout
+- Form embedded on page vs. separate page
+- Vertical vs. horizontal field alignment
+- Form above fold vs. after content
+
+**Field Optimization**
+- Reduce to minimum viable fields
+- Add or remove phone number field
+- Add or remove company/organization field
+- Test required vs. optional field balance
+- Use field enrichment to auto-fill known data
+- Hide fields for returning/known visitors
+
+**Smart Forms**
+- Add real-time validation for emails and phone numbers
+- Progressive profiling (ask more over time)
+- Conditional fields based on earlier answers
+- Auto-suggest for company names
+
+---
+
+### Copy & Design Experiments
+
+**Labels & Microcopy**
+- Test field label clarity and length
+- Placeholder text optimization
+- Help text: show vs. hide vs. on-hover
+- Error message tone (friendly vs. direct)
+
+**CTAs & Buttons**
+- Button text variations ("Submit" vs. "Get My Quote" vs. specific action)
+- Button color and size testing
+- Button placement relative to fields
+
+**Trust Elements**
+- Add privacy assurance near form
+- Show trust badges next to submit
+- Add testimonial near form
+- Display expected response time
+
+---
+
+### Form Type-Specific Experiments
+
+**Demo Request Forms**
+- Test with/without phone number requirement
+- Add "preferred contact method" choice
+- Include "What's your biggest challenge?" question
+- Test calendar embed vs. form submission
+
+**Lead Capture Forms**
+- Email-only vs. email + name
+- Test value proposition messaging above form
+- Gated vs. ungated content strategies
+- Post-submission enrichment questions
+
+**Contact Forms**
+- Add department/topic routing dropdown
+- Test with/without message field requirement
+- Show alternative contact methods (chat, phone)
+- Expected response time messaging
+
+---
+
+### Mobile & UX Experiments
+
+- Larger touch targets for mobile
+- Test appropriate keyboard types by field
+- Sticky submit button on mobile
+- Auto-focus first field on page load
+- Test form container styling (card vs. minimal)
+
+---
+
 ## Questions to Ask
 
 If you need more context: