Call the record's boxes what they are

The offer names are from the protocol before this one, where a widget was
drawn twice and the record had to say which drawing was the question. It
is asked once now, so offer_part is the part it was asked in, offer_place
the place it was asked at, and place where its drawing was put: part,
asked and placed. LayoutHolds::frame is a range on the window since the
frame became a length of one, and the frame's own entry is the frame_len
pin beside it, so it is window; Painter::frame_own goes with it.
answers_at had one caller and said less than the line that replaces it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/scenario/mod.rs

@@ -407,7 +407,7 @@ fn record(id: WidgetId, h: &Harness) -> String {
     let active = &h.render.active[&id];
     format!(
         "frame {} ask {} box {} size {}",
-        active.frame, active.offer_part, active.extent, active.size,
+        active.frame, active.part, active.extent, active.size,
     )
 }