Add ability to select node/edge from search result

In the search result UI the user can add/remove the node/edge. They should also be able to select the node/edge in the graph if it is already in the graph.

We could also add options to add the node/edge to the current selection, or spotlight the node (dim all the other nodes similar to the table filter).

Start at the search result UI and trace its existing add/remove behavior into graph selection. Confirm whether the requested scope includes only selecting an already-present node or edge, or also the optional current-selection and spotlight behaviors. Done means the agreed search-result action reliably selects the matching graph element.

Written by the indexing model from the issue text.