Run 12: knowledge system, mortality, and the North's generational soul

SPEC §5 built: three skill domains (forage/woodcraft/masonry) that pay
off and grow by practice; proximity diffusion soul-calibrated by
absorption x teaching-drive; and mortality - the piece that makes
knowledge generational. Elders die (~150-230 days), everything unshared
dies with them, a youth comes of age near knowing nothing. North soul
(absorption 1.6, teaching 0.9) vs South (1.0, 0.3); East teaches no one.

Two findings: (1) headless soaks were contaminated by orphaned child
processes writing later runs' CSVs - fixed with StopAfterDays clean
self-terminate; (2) passive diffusion barely helped - the North's real
culture is the young seeking elders on purpose, so added deliberate
teacher-seeking and youths now cradle beside the wisest elder. North
now leads knowledge at every checkpoint, but a stable town approaches
the ceiling regardless, so teaching is a recovery advantage not an
equilibrium one. The crisis-recovery experiment is the real test, noted
in FINDINGS as next.

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

scripts/SoulProfile.cs

@@ -53,6 +53,12 @@ public class SoulProfile
     public float StatusBias;      // West: visible-wealth preference (unused in MVP)
     public float Accumulation;    // East: hoarding pressure (unused in MVP)
 
+    // Knowledge culture (SPEC §5): how readily this soul absorbs from
+    // others, and how deliberately it passes on what it knows. The North's
+    // whole identity lives in these two numbers.
+    public float Absorption = 1f;     // learning rate multiplier
+    public float TeachingDrive = 0f;  // how much being near this soul teaches
+
     public static SoulProfile NatureSoul() => new()
     {
         Type           = SoulType.Nature,
@@ -61,6 +67,8 @@ public class SoulProfile
         CommunityBias  = 0.8f,
         StatusBias     = 0.1f,
         Accumulation   = 0.1f,
+        Absorption     = 1.0f,
+        TeachingDrive  = 0.3f,   // knowledge passes casually, by living together
     };
 
     /// <summary>
@@ -77,6 +85,8 @@ public class SoulProfile
         CommunityBias  = 0.95f,
         StatusBias     = 0.15f,
         Accumulation   = 0.2f,
+        Absorption     = 1.6f,   // raised to receive what elders hand down
+        TeachingDrive  = 0.9f,   // and to hand it down in turn — the whole culture
     };
 
     /// <summary>
@@ -92,5 +102,7 @@ public class SoulProfile
         CommunityBias  = 0.1f,
         StatusBias     = 0.5f,
         Accumulation   = 0.9f,
+        Absorption     = 0.7f,   // they take, but rarely sit still to learn
+        TeachingDrive  = 0.0f,   // and teach no one anything, ever
     };
 }