Expansion phase: settlements — the North joins the world

Runs 5-6 logged in FINDINGS.md (soul layer validated: nature debris
0.000 vs selfish 0.225 after two years; the ledger works).

Towns are now real spatial structure: TownDef seeds (South at the
bottom of the map, North at the top), NPCs affiliate with a home town,
communal duty serves your own settlement (buildings are town-tagged,
founding uses the town centroid and per-town shelter caps), and each
town raises its own shelters and granary. Generational (North) soul
profile added — temperament only until the knowledge system lands.
Map shows town labels; rosters and CSVs carry town columns.

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

scripts/Building.cs

@@ -21,6 +21,9 @@ public class Building
     public BuildingKind Kind = BuildingKind.Shelter;
     public Vector2 Site;
 
+    /// <summary>Which settlement this building belongs to.</summary>
+    public string Town = "";
+
     public static Building NewShelter(Vector2 site) => new()
     {
         Kind = BuildingKind.Shelter,