/// [`crate::arith::clamp_u32`] / their own bound.
/// - Precision at the endpoints is not guaranteed to be exact: for very
/// large `a` or `b`, catastrophic cancellation in `b - a` can lose
/// bits. The algebraic form `a + (b - a) * t` is chosen for
/// monotonicity, not for bitwise endpoint accuracy.
///
/// Does not panic.
/// Linear interpolation for `f64`.
///
/// # Edge cases
/// Same IEEE-754 semantics as [`lerp_f32`]: NaN propagates, infinities
/// follow standard arithmetic, `t` outside `[0, 1]` extrapolates. Does
/// not panic.