Expands ShopTowns and ShopSamples to validate the shop regions added for
the remaining towns across every facet, using real vendor coordinates.
Fixes the parent-town lookup and the overlap exemption to handle towns
that are themselves nested under a non-town region (e.g. Jhelom under
"Jhelom Islands"): the town is now matched by region type rather than by
Parent == null, and a shop may overlap any ancestor region since
Region.Find resolves to the deepest child.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
c709faf3bb