fix: enforce storage and tooling invariants

simulation/state/StorageStateRecord.gd

@@ -2,6 +2,7 @@ class_name StorageStateRecord
 extends RefCounted
 
 const SCHEMA_VERSION := 1
+const DEFAULT_CAPACITY := 100.0
 
 var data: Dictionary
 
@@ -11,7 +12,7 @@ func _init(record_data: Dictionary = {}) -> void:
 
 
 static func create(
-	storage_id: StringName, initial_amounts: Dictionary, capacity: float = 100.0
+	storage_id: StringName, initial_amounts: Dictionary, capacity: float = DEFAULT_CAPACITY
 ) -> StorageStateRecord:
 	return StorageStateRecord.new(
 		{
@@ -32,12 +33,28 @@ static func from_dictionary(record_data: Dictionary) -> StorageStateRecord:
 		return null
 	if not record_data["amounts"] is Dictionary:
 		return null
+	var capacity := float(record_data["capacity"])
+	if not is_finite(capacity) or capacity < 0.0:
+		return null
 	var normalized := record_data.duplicate(true)
 	normalized["schema_version"] = SCHEMA_VERSION
-	normalized["capacity"] = float(record_data["capacity"])
+	normalized["capacity"] = capacity
 	var normalized_amounts := {}
-	for item_id in record_data["amounts"]:
-		normalized_amounts[String(item_id)] = float(record_data["amounts"][item_id])
+	var total_amount := 0.0
+	for raw_item_id in record_data["amounts"]:
+		var item_id := String(raw_item_id)
+		var amount := float(record_data["amounts"][raw_item_id])
+		if (
+			item_id.is_empty()
+			or normalized_amounts.has(item_id)
+			or not is_finite(amount)
+			or amount < 0.0
+		):
+			return null
+		total_amount += amount
+		if not is_finite(total_amount) or total_amount > capacity:
+			return null
+		normalized_amounts[item_id] = amount
 	normalized["amounts"] = normalized_amounts
 	return StorageStateRecord.new(normalized)
 
@@ -62,6 +79,8 @@ func get_available_capacity() -> float:
 
 
 func deposit(item_id: StringName, requested_amount: float) -> float:
+	if item_id.is_empty() or not is_finite(requested_amount) or requested_amount <= 0.0:
+		return 0.0
 	var accepted := minf(maxf(requested_amount, 0.0), get_available_capacity())
 	if accepted <= 0.0:
 		return 0.0
@@ -70,6 +89,8 @@ func deposit(item_id: StringName, requested_amount: float) -> float:
 
 
 func withdraw(item_id: StringName, requested_amount: float) -> float:
+	if item_id.is_empty() or not is_finite(requested_amount) or requested_amount <= 0.0:
+		return 0.0
 	var removed := minf(maxf(requested_amount, 0.0), get_amount(item_id))
 	if removed <= 0.0:
 		return 0.0