davdittrich/robscale: robscale 0.1.0

Changes since v0.1.0 Consistent NA handling: adm() now raises an error when na.rm = FALSE and NAs are present, matching robLoc() and robScale() behavior. Replaced manual new[]/delete[] with std::unique_ptr for RAII memory safety in all C++ estimator functions. Removed unused scoring-iteration constants (PSI_NORM_CONST, INV_PSI_NORM_CONST) from robust_core.h. Hoisted loop-invariant half_inv_s above the Newton--Raphson loop in rob_loc.cpp. Added Mermaid algorithm flowcharts for robLoc and robScale to README. Expanded test suite: explicit-center tests for adm(), maxit edge cases for robLoc() and robScale(), sorting network verification for n = 2--8. Added cph role to Authors@R in DESCRIPTION. Softened "branchless" claim in README to reflect conditional swap reality. Updated install instructions for CRAN availability.