Run 10: organic recovery achieved - minerals are not a commons

Recovery blocker was material, not motivational. Two fixes: (1) harvest
floors and commons debris apply only to living, regenerating resources -
stone does not regrow, so "leave half" merely stranded the world supply
and kept the homeless homeless forever; minerals now quarry to depletion
for every soul equally. (2) Matter conservation: idle variety-gathering
touches only renewables, and packs may only shed what the land replaces
- lossy make-room had milled 900+ stone to dust during demand flapping.

Verified over 260 headless days: year-1 winter still wrecks the naive
town, it rebuilds in 20 days, famine survivors found the first granaries
from hunger memory, and year-2 winter passes with zero ruins on stored
reserves. The town has a history now: naive youth, catastrophe,
learning, resilient maturity.

Remaining tuning in FINDINGS.md: granary sprawl, post-famine nourishment.

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

scripts/NPC.cs

@@ -78,6 +78,11 @@ public class Npc
     /// who they are becoming. Indexed by (int)NpcState.</summary>
     public int[] StateTicksToday = new int[5];
 
+    // --- Diagnostics (read-only views for the stats logger) ---------------
+    public MaterialKind CurrentDemand(GameManager gm) => PickGatherTarget(gm);
+    public int RoughNights => _unshelteredRests;
+    public bool HungerMemory => _hungerMemory;
+
     public NpcState DominantStateToday()
     {
         int best = 0;
@@ -116,6 +121,17 @@ public class Npc
     private static readonly MaterialKind[] GatherKinds =
         { MaterialKind.Wood, MaterialKind.Stone, MaterialKind.Clay };
 
+    // Idle variety only touches what regrows. Minerals are mined on purpose
+    // (construction, a roof of your own) — never as a hobby. Run 10 taught
+    // us that idle mining + lossy packs can mill a world's stone to dust.
+    private static readonly MaterialKind[] VarietyKinds =
+        { MaterialKind.Wood, MaterialKind.Food };
+
+    // What a pack may shed to make room: only matter the land replaces.
+    // Set-down stone is stone destroyed — and the world doesn't make more.
+    private static readonly MaterialKind[] DroppableKinds =
+        { MaterialKind.Wood, MaterialKind.Food, MaterialKind.Clay };
+
     /// <summary>
     /// One simulation tick = one in-game minute (SPEC §9).
     /// Order per SPEC §10: vitals check → day/night bias → state behavior → fatigue.
@@ -253,9 +269,9 @@ public class Npc
                     return MaterialKind.Wood;
         }
 
-        MaterialKind best = GatherKinds[(int)(Mathf.Abs(PersonalityModifier) * 100f) % GatherKinds.Length];
+        MaterialKind best = VarietyKinds[(int)(Mathf.Abs(PersonalityModifier) * 100f) % VarietyKinds.Length];
         float least = float.MaxValue;
-        foreach (var kind in GatherKinds)
+        foreach (var kind in VarietyKinds)
         {
             Inventory.TryGetValue(kind, out float have);
             if (have < least) { least = have; best = kind; }
@@ -292,7 +308,7 @@ public class Npc
         Inventory.TryGetValue(demanded, out float haveDemanded);
         if (haveDemanded >= EffectiveCapacity * 0.25f) return;
 
-        foreach (var kind in GatherKinds)
+        foreach (var kind in DroppableKinds)
         {
             if (kind == demanded) continue;
             if (TotalCarried() <= EffectiveCapacity * 0.5f) break;