piqp 0.6.4.1

Fix undefined behavior reported by CRAN’s gcc-UBSAN checks: the dense backend’s KKT constructor move-assigned a freshly constructed Eigen::LLT, whose m_info member released Eigen (3.4.x and 5.0.x) leaves uninitialized. The Cholesky object is now initialized by factorizing a full-size zero matrix, which also keeps all memory allocation in setup. This is the fix merged upstream in PIQP (PREDICT-EPFL/piqp#45), applied to the vendored v0.6.4 sources through the package’s patch file.
R CMD build with R-devel no longer leaves the src/.r_patched marker in the tarball: a clean rule in src/Makevars now removes it.
New on-demand GitHub Actions workflow sanitizers.yaml that checks the package in the r-hub gcc16, gcc-asan, and clang-ubsan containers.

piqp 0.6.4

Update to v0.6.4 of the underlying PIQP library
Compatibility with Eigen 5 (replaces removed EIGEN_NOEXCEPT macro), required for upcoming RcppEigen release (#6)

Update to v0.6.2 of the underlying PIQP library
Migrate from R6 to S7 OOP system
Inequality constraints are now double-sided: h_l <= Gx <= h_u
Variable bounds renamed: x_lb/x_ub to x_l/x_u
Result fields renamed: z to z_l/z_u, z_lb/z_ub to z_bl/z_bu, s to s_l/s_u, s_lb/s_ub to s_bl/s_bu
Info fields renamed: primal_inf to primal_res, dual_inf to dual_res
New settings: infeasibility_threshold, preconditioner_reuse_on_update
Use generic functions solve(), update(), get_settings(), get_dims(), and update_settings() instead of R6 methods
Support for problem data updates and warm starts via update()