I think it's done!
– The "OUTLINE" container contains structural notes such as chapters, topics, etc and complementary notes such as ideas and references. Structural notes have the prototype = "map_item".
– the prototype stores the name of the parent note in the $parentName variable by applying the rule:
Code:$parentName=$Name(parent);
– The "MAP_aliases" agent collects the structural notes from the "OUTLINE" as aliases with the query
Code:descendedFrom("OUTLINE") & $Prototype = "map_item";
and then applies to them the action
Code:linkTo(find(descendedFrom("MAP_aliases") & $IsAlias & $Name=$parentName(that)));
And this is it. If I add a structural note to the outline, it will appear in the agent's map view linked to its parent. If something funny goes on on this map view, I can delete all items at once and they will be recreated with the links.
Now it only remains some styling and layout to do with the map view – arranging chapters, subchapters and topics in some kind of hierarchy (although this can be done manually).
Thanks for pointing me in the right direction!
SOME IMAGES:THE THREE OBJECTS: outline with originals, prototype, and agent with aliases

The Outline: originals with the prototype applied to the items to appear on the agent's map

The Agent: map view with automatic links