feat: refactor Database to use Command messages instead of direct EntityManager

[atournayre]

Summary

This PR refactors the Database class to use Symfony's Command/Handler pattern instead of directly using Doctrine's EntityManager. This architectural change improves separation of concerns and testability while maintaining full backward compatibility.

Key Changes

• Database Class Refactoring: Replace EntityManagerInterface with CommandBusInterface
• New Command Messages:
  • DatabasePersistCommand for persist operations
  • DatabaseRemoveCommand for remove operations
  • DatabaseFlushCommand for flush operations
• Command Handlers: Corresponding handlers that encapsulate Doctrine operations
• SyncCommandInterface: New interface for synchronous command execution
• Handler Interfaces: Following Elegant Object principles
• Documentation Updates: Updated database.md and domain-events.md
• Test Fixes: Updated unit tests to work with command-based architecture

Benefits

• Better Architecture: Separation of concerns through command/handler pattern
• Improved Testability: Commands can be easily mocked and tested
• Future Extensibility: Easy to add middleware, events, or additional logic
• Backward Compatibility: Public API remains unchanged
• Code Quality: All tests pass, PHPStan clean

Testing

• ✅ All 735 tests pass (1275 assertions)
• ✅ PHPStan analysis passes without errors
• ✅ Existing API contracts maintained
• ✅ Handler interfaces follow Elegant Object principles

Test plan

• Verify all existing Database functionality works as expected
• Test command dispatching and handler execution
• Validate backward compatibility with existing code
• Confirm PHPStan and code quality standards are met

🤖 Generated with Claude Code