Previously, _get_promoted_widget_context_cache_key included widgets_values
from context nodes, so changing a widget inside a promoted subgraph
invalidated the entire cache snapshot even when promotion topology and
other nodes were unchanged.
This makes promoted-context snapshots key off node structure and
topology only, while individual nodes are still reanalyzed when their
widgets_values actually change.
When a subgraph exposes a promoted widget and the instance value or connected
inner widget contains a usable model path, create a top-level model reference
on the subgraph node instead of only pointing to the inner definition node.
This lets resolution, location, and queue updates target the instance widget
directly.
Also handle serialized subgraph instances that omit proxyWidgets by
reconstructing the same promotion from subgraph input/link metadata, and
extend widget values for promoted inputs in the workflow updater.
Dariusz L