missForest 1.6 - the ranger upgrade

This release modernizes missForest for current R environments and future development while maintaining full backward compatibility.

Highlights

• New default backend: switched from randomForest to ranger for faster, more memory-efficient imputation.
• Backward compatibility: the legacy randomForest backend remains available via the backend = "randomForest" option.
• Improved parallelization: more robust handling of parallel backends (foreach, doParallel, doRNG) with consistent RNG behavior.
• Refreshed documentation: updated help pages, vignette, and README for clarity and reproducibility.
• CITATION and metadata updates: replaced deprecated citEntry() with bibentry(), added Authors@R, and integrated Rdpack references.
• Codebase cleanup: reduced redundant imports, resolved namespace conflicts, and improved cross-platform compliance.

Maintainer update

Maintainer email updated from stekhoven@stat.math.ethz.ch to stekhoven@nexus.ethz.ch.

Compatibility

• Tested on R 4.4 and 4.5 across macOS (arm64), Linux (Ubuntu 22.04), and Windows (win-builder).
• No known breaking changes for existing users or scripts.