feat: add NPC schedules with sleep, meal, and work periods

Add ACTION_SLEEP with home-position targeting and energy restoration. Embed schedule periods (SLEEP/MEAL/WORK/DISCRETIONARY) in ActionSelectionSystem with TimeOfDay from SimulationClock. NPCs sleep at night when energy is low, eat during meal periods when hungry, and work/discretionary the rest of the cycle. Home position stored per NPC and serialized through NPCStateRecord with backward-compatible fallback. Cycle duration persisted through save/restore. Includes headless test for sleep period, work period, meal hunger, energy restoration, serialization round-trip, and home targeting without world adapter.

simulation/actions/ActionSelectionSystem.gd

@@ -1,10 +1,56 @@
 class_name ActionSelectionSystem
 extends RefCounted
 
+enum SchedulePeriod {
+	WORK,
+	SLEEP,
+	MEAL,
+	DISCRETIONARY
+}
 
-func select_action(npc: SimNPC, village: SimVillage) -> ActionSelectionResult:
+const SLEEP_BEGIN := 0.88
+const SLEEP_END := 0.15
+const BREAKFAST_BEGIN := 0.25
+const BREAKFAST_END := 0.35
+const DINNER_BEGIN := 0.7
+const DINNER_END := 0.8
+const WORK_BEGIN := 0.28
+const WORK_END := 0.85
+
+
+func select_action(npc: SimNPC, village: SimVillage, time_of_day: float = 0.5) -> ActionSelectionResult:
 	if npc.is_dead:
 		return null
+
+	var period := _get_period(time_of_day)
+
+	if period == SchedulePeriod.SLEEP:
+		if npc.energy < 60.0:
+			return ActionSelectionResult.new(
+				SimulationIds.ACTION_SLEEP, -1.0, "Night-time sleep; energy is low"
+			)
+		if npc.hunger > 75.0 and npc.get_inventory_amount(SimulationIds.RESOURCE_FOOD) >= 1.0:
+			return ActionSelectionResult.new(
+				SimulationIds.ACTION_EAT, -1.0, "Night-time hunger; eating from inventory"
+			)
+		return ActionSelectionResult.new(
+			SimulationIds.ACTION_SLEEP, -1.0, "Night-time; going home"
+		)
+
+	if period == SchedulePeriod.MEAL:
+		if npc.hunger > 50.0:
+			if npc.get_inventory_amount(SimulationIds.RESOURCE_FOOD) >= 1.0:
+				return ActionSelectionResult.new(
+					SimulationIds.ACTION_EAT, -1.0, "Meal-time hunger; eating from inventory"
+				)
+			if village.food > 0:
+				return ActionSelectionResult.new(
+					SimulationIds.ACTION_WITHDRAW_FOOD, -1.0, "Meal-time; pantry has food"
+				)
+			return ActionSelectionResult.new(
+				SimulationIds.ACTION_GATHER_FOOD, -1.0, "Meal-time hunger; pantry is empty"
+			)
+
 	if npc.is_starving:
 		if npc.get_inventory_amount(SimulationIds.RESOURCE_FOOD) >= 1.0:
 			return ActionSelectionResult.new(
@@ -37,6 +83,14 @@ func select_action(npc: SimNPC, village: SimVillage) -> ActionSelectionResult:
 		return ActionSelectionResult.new(
 			SimulationIds.ACTION_REST, -1.0, "Energy is below the rest threshold"
 		)
+
+	if period == SchedulePeriod.DISCRETIONARY:
+		var roll := npc.random_source.randf()
+		if roll < 0.3:
+			return ActionSelectionResult.new(
+				SimulationIds.ACTION_WANDER, -1.0, "Discretionary wander"
+			)
+
 	return _choose_best_work_action(npc, village)
 
 
@@ -129,3 +183,23 @@ func _calculate_score(
 	if npc.debug_logs:
 		print("[ActionSelection] ", npc.npc_name, " score ", action_id, " = ", score)
 	return score
+
+
+static func _get_period(time_of_day: float) -> int:
+	if _in_wrap_range(time_of_day, SLEEP_BEGIN, SLEEP_END):
+		return SchedulePeriod.SLEEP
+	if _in_range(time_of_day, BREAKFAST_BEGIN, BREAKFAST_END):
+		return SchedulePeriod.MEAL
+	if _in_range(time_of_day, DINNER_BEGIN, DINNER_END):
+		return SchedulePeriod.MEAL
+	if _in_range(time_of_day, WORK_BEGIN, WORK_END):
+		return SchedulePeriod.WORK
+	return SchedulePeriod.DISCRETIONARY
+
+
+static func _in_range(value: float, begin: float, end: float) -> bool:
+	return value >= begin and value <= end
+
+
+static func _in_wrap_range(value: float, begin: float, end: float) -> bool:
+	return value >= begin or value <= end