Run 15: known-nodes exploration (addendum stage 1), per-town debug, O(n^2) fix

Exploration addendum stage 1: per-NPC known-nodes. NPCs gather only from
resources they've personally sensed (radius 22) or been told about;
founders seed with home ground, children inherit parents' maps, node
knowledge diffuses between neighbors like skills. Starving NPCs venture
outward and sense as they go - non-random needs-driven exploration, the
seed of first contact. Repopulation preserved (seeding + survival food
fallback): all towns fed, population stable 86-109 over 240 days.

Debug screen rebuilt: the ~68-row per-villager roster (overflowing at
four-town scale) replaced with a per-town summary - pop, fed%, knowledge,
debris, state breakdown, buildings, culture-colored, plus world
births/deaths. Scales to any population.

Performance: added phase timers and measured instead of guessing - npc.Tick
was 94% of cost, O(n^2) via TickResting calling RestingOccupancy (full
population scan) per building per resting NPC. Fixed with a once-per-tick
occupancy cache on Building. npc phase ~4x faster and now linear; full
240-day four-town run in 180s, faster than the pre-exploration baseline.
Profiling scaffolding removed.

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

scripts/GameManager.cs

@@ -123,6 +123,10 @@ public partial class GameManager : Node2D
                     LifeExpectancyDays = 150 + rng.Next(0, 80),
                 };
                 npc.Know.Capacity = 1.0f + (float)rng.NextDouble();
+                // Founders know their home ground — the resources around the
+                // town seed. They begin with a working local map, not blind.
+                foreach (var node in World.NodesWithin(center, 130f))
+                    npc.KnownNodes.Add(node);
                 Npcs.Add(npc);
             }
         }
@@ -308,6 +312,10 @@ public partial class GameManager : Node2D
                 LifeExpectancyDays = 150 + rng.Next(0, 80),
             };
             child.Know.Capacity = 1.0f + (float)rng.NextDouble();
+            // A child inherits its parents' map — the family's known grounds,
+            // passed down like everything else a generation hands forward.
+            foreach (var node in a.KnownNodes) child.KnownNodes.Add(node);
+            foreach (var node in b.KnownNodes) child.KnownNodes.Add(node);
             newborns.Add(child);
             BirthsToday++;
             pop[a.HomeTown] = (int)townPop + 1;   // count the newborn toward capacity
@@ -331,6 +339,23 @@ public partial class GameManager : Node2D
     {
         Grid.Rebuild(Npcs);
 
+        // Recompute shelter occupancy once per tick (was O(n²): each resting
+        // NPC re-scanned everyone, per building). Now: one pass, cached — each
+        // sleeper counts toward the nearest shelter they're actually inside.
+        foreach (var b in Buildings) b.Occupancy = 0;
+        foreach (var npc in Npcs)
+        {
+            if (npc.State != NpcState.Resting) continue;
+            Building? at = null; float best = 6.25f;   // within 2.5 units
+            foreach (var b in Buildings)
+            {
+                if (b.RestCapacity <= 0) continue;
+                float d = npc.Position.DistanceSquaredTo(b.Site);
+                if (d < best) { best = d; at = b; }
+            }
+            if (at != null) at.Occupancy++;
+        }
+
         TotalTicks++;
 
         foreach (var npc in Npcs)
@@ -349,7 +374,7 @@ public partial class GameManager : Node2D
             TickReproduction();
             StatsLogger.LogDay(this);
             if (Day % 10 == 0)
-                GD.Print($"[WorldSim] Day {Day} complete.");
+                GD.Print($"[WorldSim] Day {Day} complete (pop {Npcs.Count}).");
 
             if (StopAfterDays > 0 && Day >= StopAfterDays)
             {