Update integration for dancing-links v3.4.0 interface changes

[TimBeyer]

Upgrade sudoku-dlx to support the new interface of dancing-links v3.4.0. This includes:

• Refactoring code to accommodate any breaking changes or new method signatures
• Updating dependency to dancing-links v3.4.0
• Ensuring all functionality and tests work with the upgraded library
• Documenting interface changes in the code as needed

This should be done as a separate ticket from general dependency and DX upgrades.