vol2: removeAllRules not implemented — package removal from RuleBase is a no-op

[mdproctor]

Context

RuleBase.apply() has a removeAllRules() stub marked @todo. Package removal from a ChangeSet is currently ignored.

Required

Implement rule removal: unsubscribe Rete nodes, update UnitDescriptor containers, call engine.apply(removed=[...]) for all rules in the removed package.

Refs #6724