v0.19.1

Added

• let callers choose the binomial sampling algorithm

Fixed

• Correct exact distribution boundaries
• Beta::sf returning exactly 1.0 for tiny x
• order the selection fast paths by total_cmp, not <=
• replace hand-rolled quickselect with select_nth_unstable_by
• address review on the BINV/BTPE sampler

Other

• Alias f64 constants
• Fix nightly f64 deprecation warnings
• add a selection benchmark, and ordered fast paths it exposed
• build the NaN order-statistic test under no_std
• move binomial sampling into its own module
• split the sampler's branch selection out of the RNG path
• require std for the BTPE chi-square test
• sample Binomial via BINV/BTPE instead of n Bernoulli trials
• Bound the Newton iteration count and cover the quantile guards
• Add safeguarded-Newton inverse_cdf for Chi and InverseGamma