fix: a hole placed on a face follows the face along its axis only, and warns when off the face (#510)

A hole positioned on a face now follows that face along the hole's own axis instead of sliding to the face's nearest point. When the face no longer reaches the position, the hole stays where it was placed and the feature says so.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/book/src/dev/naming.md

@@ -80,6 +80,12 @@ longer lies on the face says so: `face ... was found by geometry, not exact hist
 An edge name is found as the edge between the two faces it names, each found as above: when
 exactly one edge runs between them it is that edge, even after a split of one of its faces.
 
+A hole placed by a position on a face is the exception to "the point nearest the reference's
+point": its position is a place, not a pick. The hole follows its face along its own axis, so it
+moves with the face when the face moves, and when the face no longer reaches the position it stays
+where it was placed and the feature says so, instead of sliding to the face's edge and drilling
+half a hole there. (Holes at sketch points follow their sketch.)
+
 ## Older designs
 
 Designs saved before format 14 stored names worked out from geometry, and a few of them name a