South town MVP: world sim, seasons, granary, contrast test + findings

Godot 4.7 C# world simulation per SPEC.md (with 2026-07-21 amendments).
15 NPCs, 5-state machine, demand-driven work, soul-imprint triad data
model, seasons with winter frost, granary, need-based gift economy,
selfish-soul contrast wiring, daily/per-villager/gift CSV logging.

FINDINGS.md documents the four soak experiments: the dead paradise,
the buffers winning, the emergent hungry gap, and the contrast test
proving the four-town thesis (and that selfishness wins until the
soul-consequence layer exists).

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

scripts/GameManager.cs

@@ -0,0 +1,126 @@
+using System.Collections.Generic;
+using Godot;
+
+namespace WorldSim;
+
+/// <summary>
+/// Main loop and time system (SPEC §9).
+/// 1 tick = 1 in-game minute; 1440 ticks = 1 day.
+/// Day/night drives activity bias: gather/build by day, rest/socialize by night.
+/// </summary>
+public partial class GameManager : Node2D
+{
+    public static GameManager? Instance { get; private set; }
+
+    [Export] public int Seed = 12345;
+    [Export] public int NpcCount = 15;
+
+    [Export(PropertyHint.Range, "0,15,1")]
+    public int SelfishCount = 3;             // the contrast test (SPEC §11 amendment)
+
+    [Export(PropertyHint.Range, "1,2000,1")]
+    public float TicksPerRealSecond = 20f;   // sim speed; ~1500 ≈ one day/sec for soaks
+
+    public World World { get; private set; } = null!;
+    public List<Npc> Npcs { get; } = new();
+    public List<Building> Buildings { get; } = new();
+
+    public long TotalTicks { get; private set; }
+    public int Day => (int)(TotalTicks / 1440);
+    public int MinuteOfDay => (int)(TotalTicks % 1440);
+    public bool IsNight => MinuteOfDay < 6 * 60 || MinuteOfDay >= 22 * 60;
+
+    // --- Seasons: the pressure that makes community structure matter ------
+
+    [Export] public int DaysPerSeason = 30;
+
+    public int SeasonIndex => (Day / DaysPerSeason) % 4;
+
+    public string SeasonName => SeasonIndex switch
+    {
+        0 => "spring", 1 => "summer", 2 => "autumn", _ => "winter",
+    };
+
+    /// <summary>Food regen multiplier — winter gives almost nothing.</summary>
+    public float SeasonFoodMult => SeasonIndex switch
+    {
+        0 => 1.5f, 1 => 1.0f, 2 => 0.8f, _ => 0.05f,
+    };
+
+    /// <summary>Wood regen multiplier — growth slows in the cold.</summary>
+    public float SeasonWoodMult => SeasonIndex switch
+    {
+        0 => 1.2f, 1 => 1.0f, 2 => 1.0f, _ => 0.4f,
+    };
+
+    private double _tickAccumulator;
+
+    public override void _Ready()
+    {
+        Instance = this;
+        TotalTicks = 8 * 60;   // start at 08:00 — day one begins mid-morning, not asleep
+        World = new World(Seed);
+        World.Generate();
+        SpawnNpcs();
+        StatsLogger.Init();
+        GD.Print($"[WorldSim] World generated (seed {Seed}), {Npcs.Count} NPCs dropped in.");
+    }
+
+    private void SpawnNpcs()
+    {
+        // Dropped near the map center with scatter — no scripted town layout.
+        // Where the community forms is the experiment (SPEC §11).
+        var rng = new System.Random(Seed);
+        for (int i = 0; i < NpcCount; i++)
+        {
+            bool selfish = i >= NpcCount - SelfishCount;
+            Npcs.Add(new Npc
+            {
+                Name = $"Villager_{(char)('A' + i)}",
+                Soul = selfish ? SoulProfile.SelfishSoul() : SoulProfile.NatureSoul(),
+                PersonalityModifier = (float)(rng.NextDouble() * 0.4 - 0.2),
+                Position = new Vector2(
+                    World.GridSize / 2f + rng.Next(-20, 21),
+                    World.GridSize / 2f + rng.Next(-20, 21)),
+            });
+        }
+    }
+
+    public override void _Process(double delta)
+    {
+        _tickAccumulator += delta * TicksPerRealSecond;
+        while (_tickAccumulator >= 1.0)
+        {
+            _tickAccumulator -= 1.0;
+            Tick();
+        }
+    }
+
+    /// <summary>Where the community's feet actually are — new communal
+    /// buildings are founded here, not at a scripted town center.</summary>
+    public Vector2 CommunityCentroid()
+    {
+        if (Npcs.Count == 0) return new Vector2(World.GridSize / 2f, World.GridSize / 2f);
+        Vector2 sum = Vector2.Zero;
+        foreach (var npc in Npcs) sum += npc.Position;
+        return sum / Npcs.Count;
+    }
+
+    private void Tick()
+    {
+        TotalTicks++;
+
+        foreach (var npc in Npcs)
+            npc.Tick(World, this);
+
+        if (TotalTicks % 1440 == 0)
+        {
+            World.RegenerateDaily(SeasonFoodMult, SeasonWoodMult);
+            foreach (var building in Buildings)
+                building.DailyUpkeep();
+            StatsLogger.LogDay(this);
+            if (Day % 10 == 0)
+                GD.Print($"[WorldSim] Day {Day} complete.");
+        }
+    }
+}