vecmatch 1.3.0

Major changes

Refactored and unified the S3 class system across the package, and added helper methods for inspecting the internal structure of vecmatch objects.
Added get_select_params() and run_selected_matching() to streamline the re-estimation step after the main optimization workflow.
Reduced and cleaned up package dependencies in DESCRIPTION, and improved how suggested packages are handled in the code.

Fixed a bug in raincloud(), where facet labels were reversed when using facet.
Removed backend handling from optimize_gps(). The parallel backend must now be registered outside the function.
Updated the optimization vignette to use run_selected_matching().
Corrected a typo in the cancer dataset.
Added examples for all exported functions and wrapped long-running examples in \donttest{}.
Updated badges in the README.
Added automated tests to check reproducibility of results.

Added optimize_gps(), make_opt_args(), and select_opt() to support a new GPS‐optimization workflow.
Modified csregion() so the GPS can be reestimated after dropping observations.

Fixed factor handling in raincloud() and mosaic(), now allowing custom facet ordering via releveling.
Added SMD and p-value labels to raincloud().
Updated the raincloud() legend to show group names with their observation counts.

csregion() now allows specifying how to handle observations at the borders of the Common Support Region (CSR) using the new borders argument.
match_gps() has been updated to support datasets with only two unique treatment groups.