Fixed the construction of the cumulative distribution function
used by simulate_lifetime() to prevent platform-dependent
numerical failures when floating-point accumulation produces values
slightly greater than one.
Added a regression test for the multiple-life simulation workflow
using simulate_lifetimes(),
mc_multilife_status(), and
mc_annuity().
This release addresses the errors reported by CRAN on macOS ARM64.
mc_annuity() examples.simulate_lifetimes() now constructs lifetime
simulations defensively when mortality inputs contain invalid terminal
values.mc_multilife_status() now uses defaults compatible with
simulate_lifetimes(): sim_id,
life_id, Kx, and Tx.