e2tree 1.0.0

New functions

goi(): Goodness of Interpretability (GoI) index measuring how well the E2Tree-estimated proximity matrix reconstructs the original ensemble proximity matrix.
goi_perm(): Permutation test for the GoI index to assess statistical significance.
goi_analysis(): Combined GoI analysis returning both the observed statistic and permutation results.
plot.goi_perm(): Plot method for goi_perm objects displaying the permutation distribution.
plot_e2tree_vis(): Interactive E2Tree visualization using visNetwork with draggable nodes, zoom/pan, and multiple layout options.
plot_e2tree_click(): Interactive E2Tree plot in the R graphics device with click-to-inspect node details.
save_e2tree_html(): Save an interactive visNetwork tree plot as a standalone HTML file.
print_e2tree_summary(): Print a formatted summary of an e2tree object.

createDisMatrix: C++ backend (CoOccurrences.cpp) with OpenMP thread-level parallelism replaces the R-level foreach/doParallel loop; co-occurrence normalization also moved to C++.
e2tree: vectorized Wt computation using vapply; simplified internal get_classes helper.
ePredTree: split rules are now pre-parsed once (parse_all_splits + apply_split_rule), eliminating repeated regex/eval(parse()) calls during prediction.
vimp: three group_by operations consolidated into one; eval/parse removed.
split: ordSplit and catSplit vectorized with outer().
eImpurity: single-step integer matrix conversion.

Fixed Rcpp type conversion (NumericVector + static_cast<int>) for ranger compatibility (ranger returns double columns for tree node assignments).
Fixed ePredTree returning character instead of double for regression trees.
Fixed bare filter() call in proximity_longer.R causing namespace conflict with dplyr.
Added missing NAMESPACE imports for graphics, grDevices, and utils.

New aaa_utils.R with shared internal helpers: e2_variance(), get_ensemble_type(), check_package().
Refactored eValidation, eImpurity, and eStoppingRules for consistency and performance.