observationFixture property
Optional canned observation. When non-null, calls to
ext.exploration.core.get_stable_observation return
{type: 'Observation', value: (observationFixture as dynamic).body}
instead of executing the binding's real handler. Other extensions
and extension tools route normally regardless.
Typed Object? to keep leonard_flutter independent of
leonard_agent; the body is read via dynamic dispatch.
Implementation
final Object? observationFixture;