Add a Blueprint Node

Recommended sequence:

1. blueprint.graph.inspect to find the target graph context.
2. blueprint.palette to find the UE Action Menu entry.
3. schema.inspect for blueprint.graph.edit operation addFromPalette.
4. blueprint.graph.edit with the selected palette entry.
5. blueprint.graph.layout if the edited region needs formatting.
6. blueprint.compile after meaningful changes.

Do not guess a K2 node class when a palette entry is available.