v2.19.0

Added

• Real-valued variables: IntervalDomain represents a continuous [min, max] range of doubles, with a new BoundedDomain<T> interface. SumConstraint and LinearConstraint (with a Double or Float bound) propagate over interval bounds using interval arithmetic, so many continuous linear-arithmetic problems are solved entirely by propagation. Build-time validation rejects BoundedDomain variables referenced by any other constraint type.
• Domain gains default isSingleton()/singleValue() methods.

Fixed

• SumConstraint/LinearConstraint propagation now dispatches Float-bound constraints to the interval-arithmetic path (previously they fell through to integer propagation and truncated fractional values).