Replace generic CRM plan with focused Zoho lead capture doc

Removes the overly generic CRM_INTEGRATION_PLAN.md and replaces it with
ZOHO_CRM_LEAD_CAPTURE.md which provides:

- Specific use cases for capturing real estate agent signups as leads
- 8 concrete events mapped to Zoho CRM API calls:
  1. New account created (signup step 1)
  2. Website created (signup step 2)
  3. Website goes live (email verified)
  4. Plan selected/changed
  5. User activity tracking (properties, customization, inquiries)
  6. Trial ending reminders
  7. Subscription activation (convert lead to customer)
  8. Subscription canceled/expired

- Custom field definitions for Zoho Leads and Deals modules
- Lead scoring system based on engagement signals
- Complete service class implementations with code examples
- OAuth setup instructions
- Sales team workflow recommendations
- Testing checklist

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: etewiah