feat: add structured economic events

tests/food_storage_loop_test.gd

@@ -110,6 +110,21 @@ func _run() -> void:
 		is_equal_approx(conserved_food, 9.0),
 		"Exactly one food unit should leave the world when eaten"
 	)
+	_check_economic_event_chain(manager)
+
+	var restored: Node = load("res://simulation/SimulationManager.gd").new()
+	restored.debug_logs = false
+	root.add_child(restored)
+	restored.set_process(false)
+	_check(
+		restored.restore_state_from_json(manager.serialize_state()),
+		"Economic events should restore with the simulation"
+	)
+	_check(
+		restored.economic_events.size() == manager.economic_events.size()
+		and restored.next_event_id == manager.next_event_id,
+		"Economic event history and its next ID should round-trip"
+	)
 
 	if failures.is_empty():
 		print("[TEST] Food storage loop passed")
@@ -122,3 +137,45 @@ func _run() -> void:
 func _check(condition: bool, message: String) -> void:
 	if not condition:
 		failures.append(message)
+
+func _check_economic_event_chain(manager: Node) -> void:
+	var expected_types: Array[StringName] = [
+		SimulationIds.EVENT_RESOURCE_EXTRACTED,
+		SimulationIds.EVENT_STORAGE_DEPOSITED,
+		SimulationIds.EVENT_STORAGE_WITHDRAWN,
+		SimulationIds.EVENT_ITEM_CONSUMED
+	]
+	_check(
+		manager.economic_events.size() == expected_types.size(),
+		"Food transfer loop should emit one structured event per transfer"
+	)
+	if manager.economic_events.size() != expected_types.size():
+		return
+	for index in expected_types.size():
+		var event: EconomicEventRecord = manager.economic_events[index]
+		_check(
+			int(event.data["event_id"]) == index
+			and StringName(event.data["event_type"]) == expected_types[index]
+			and StringName(event.data["item_id"])
+				== SimulationIds.RESOURCE_FOOD,
+			"Economic event order, identity, and item should be deterministic"
+		)
+	_check(
+		is_equal_approx(
+			float(manager.economic_events[0].data["amount"]),
+			2.0
+		)
+		and is_equal_approx(
+			float(manager.economic_events[1].data["amount"]),
+			2.0
+		)
+		and is_equal_approx(
+			float(manager.economic_events[2].data["amount"]),
+			1.0
+		)
+		and is_equal_approx(
+			float(manager.economic_events[3].data["amount"]),
+			1.0
+		),
+		"Economic events should record exact transferred quantities"
+	)

tests/npc_visual_lifecycle_test.gd

@@ -18,6 +18,24 @@ func _run() -> void:
 	var npc: SimNPC = manager.npcs[0]
 	var visual: Node3D = view.active_npc_visuals[npc.id]
 	visual.set_physics_process(false)
+	var carried_food: MeshInstance3D = visual.get_node("CarriedFood")
+	_check(not carried_food.visible, "NPC should begin without a carried-food prop")
+	npc.add_inventory(SimulationIds.RESOURCE_FOOD, 1.0)
+	manager.emit_signal(
+		"npc_inventory_changed",
+		npc,
+		SimulationIds.RESOURCE_FOOD,
+		1.0
+	)
+	_check(carried_food.visible, "Carried food should be visible on the NPC")
+	npc.remove_inventory(SimulationIds.RESOURCE_FOOD, 1.0)
+	manager.emit_signal(
+		"npc_inventory_changed",
+		npc,
+		SimulationIds.RESOURCE_FOOD,
+		0.0
+	)
+	_check(not carried_food.visible, "Deposited or eaten food should be hidden")
 
 	var resource_state: ResourceStateRecord = manager.get_resource_state(
 		&"berry_bush_01"

tests/simulation_state_serialization_test.gd

@@ -11,6 +11,7 @@ func _run() -> void:
 	_test_legacy_npc_migration()
 	_test_legacy_resource_migration()
 	_test_legacy_world_storage_migration()
+	_test_previous_world_event_migration()
 	_test_schema_rejection()
 
 	if failures.is_empty():
@@ -203,6 +204,24 @@ func _test_legacy_world_storage_migration() -> void:
 		)
 	manager.free()
 
+func _test_previous_world_event_migration() -> void:
+	var manager := _create_manager(56)
+	var previous_data: Dictionary = manager.create_state_record().to_dictionary()
+	previous_data["schema_version"] = (
+		SimulationStateRecord.PREVIOUS_SCHEMA_VERSION
+	)
+	previous_data.erase("economic_events")
+	previous_data["simulation"].erase("next_event_id")
+	var migrated := SimulationStateRecord.from_dictionary(previous_data)
+	_check(migrated != null, "World schema v2 should add an empty event stream")
+	if migrated != null:
+		_check(
+			migrated.economic_events.is_empty()
+			and int(migrated.simulation["next_event_id"]) == 0,
+			"World v2 migration should initialize deterministic event identity"
+		)
+	manager.free()
+
 func _create_manager(seed_value: int) -> Node:
 	var manager: Node = load("res://simulation/SimulationManager.gd").new()
 	manager.simulation_seed = seed_value