Package-level declarations

Base Library implementation defaulting every contribution (operators, clauses, primitives, functions) to empty, and providing structural equals/hashCode/toString; subclasses only need to override Library.alias plus whichever contributions they actually provide.

Base Pluggable implementation providing hasRule via a lazily-computed, cached set of rulesSignatures.

Base class for a Library that decorates an extended one, contributing everything the extended library already has plus whatever additionalOperators/additionalRules/additionalPrimitives/additionalFunctions the subclass overrides. Keeps extended's Library.alias.