Apply SCTransform normalization
Details
The validated sparse `vst.flavor = "v2"` path uses native corrected-count and residual kernels. Reference models, specified residual features, memory-conserving or deferred-residual mode, unsupported regression designs, custom VST arguments, and other flavors transparently delegate to `Seurat::SCTransform`. Legacy Seurat v5 assays with `do.correct.umi = FALSE` also delegate to preserve their output semantics.