A/B Testing + Schedule Sending Combined Feature Implementation

[kuzmany]

Summary

This PR combines A/B testing functionality with the email schedule sending feature for Mautic 7.x, providing a comprehensive email testing and scheduling solution.

Key Features

A/B Testing Functionality

• A/B Test Creation: Create A/B test variants for emails with different content
• Winner Selection: Automatic and manual winner selection based on various criteria
• Test Statistics: Comprehensive tracking of A/B test performance
• Variant Management: Easy management of email variants and their settings

Email Schedule Sending

• Email Schedule Sending: Schedule segment emails to be sent at specific times
• Schedule Form: New ScheduleSendType form for setting publish dates and continuation settings
• Continue Sending Option: Control whether emails continue sending to new contacts
• Background Sending Status: Enhanced status badges showing scheduling states

Changes Made

A/B Testing Changes

• ABTestController: New controller for managing A/B tests
• SendWinnerEmailCommand: Command for processing A/B test winners
• Email Entity: Enhanced with A/B testing capabilities
• Repository Updates: Support for A/B test queries and statistics
• UI Components: A/B test management interface

Schedule Sending Changes

• ScheduleSendAction: New action in EmailController for scheduling modal
• ScheduleSendType: Form type for scheduling options
• Email Entity: Added continueSending field for ongoing send control
• Repository Updates: Support for scheduled sending queries
• Status Enhancements: UI improvements for scheduling states

Combined Features

• Enhanced Email Entity: Support for both A/B testing and scheduling
• Unified UI: Integrated interface for both features
• Comprehensive Testing: Tests covering both A/B testing and scheduling scenarios
• Performance Optimizations: Efficient handling of both features

UI/UX Improvements

• Integrated Button Layout: A/B test and schedule buttons with proper priority ordering
• Enhanced Status Badges: Show both A/B test and scheduling information
• Unified Email List: Display both A/B test and scheduling states
• Improved Forms: Better user experience for both features

Database Changes

• A/B testing related fields in Email entity
• continueSending field for schedule sending functionality
• Enhanced indexes for performance

Test Coverage

A/B Testing Tests

• A/B test creation and management
• Winner selection functionality
• Statistics tracking
• Variant management

Schedule Sending Tests

• Schedule email for future sending
• Continue sending option functionality
• Schedule cancellation
• Background sending status

Combined Feature Tests

• A/B testing with scheduled emails
• Winner selection on scheduled emails
• Performance with both features enabled

Breaking Changes

None - this is a feature addition that maintains backward compatibility.

Performance Considerations

• Optimized queries for both A/B testing and scheduling
• Efficient caching for email statistics
• Proper indexing for performance

This PR provides a complete solution for both A/B testing and scheduled email sending, allowing users to create sophisticated email campaigns with proper testing and timing controls.