Host-side validation of one ambient-interaction 'message' event — mirrors the submit
path: marker required ('not-interaction' otherwise), sourceWidget must resolve to a
tracked widget iframe ('unknown-source'), the events array must be a non-empty list
of well-shaped WhiteboardWidgetInteractionRecords ('bad-shape'), and the
serialized batch is capped at WHITEBOARD_WIDGET_INTERACTION_MAX_CHARS
('oversize'). Accepted batches come back pre-summarized (via
SummarizeWidgetInteractions) as a WhiteboardWidgetInteractionEvent.
Host-side validation of one ambient-interaction 'message' event — mirrors the submit path: marker required (
'not-interaction'otherwise),sourceWidgetmust resolve to a tracked widget iframe ('unknown-source'), theeventsarray must be a non-empty list of well-shaped WhiteboardWidgetInteractionRecords ('bad-shape'), and the serialized batch is capped at WHITEBOARD_WIDGET_INTERACTION_MAX_CHARS ('oversize'). Accepted batches come back pre-summarized (via SummarizeWidgetInteractions) as a WhiteboardWidgetInteractionEvent.