The inner ring of the schedule slice, added on its own so it can be read
as domain modelling rather than as a diff against the old implementation:
two aggregates with their state machines, the policy value object, the
output ports the service depends on, and the errors it raises.
Nothing wires it up yet -- no existing code path changes. The service is
exercised end to end against in-memory fakes, which is what makes the
rules (overlap policy, lease handling, which write owns which timestamp)
assertable without a database at all.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
