RuntimeUiFrame

Immutable output of one successful runtime UI session frame.

The owner thread creates the frame and owns the detached, defensive snapshots of its output collections. After construction, all frame reads are safe from any thread when the contained public value contracts are honored. The frame does not retain the session, content description, retained tree, or mutable source collections. A session may return the same frame and collection instances for consecutive clean calls, so consumers must treat identity as an optimization rather than a semantic revision.