Preserve packed definition arrays in exports

vessels/VesselDefinition.gd

@@ -31,7 +31,9 @@ extends Resource
 # gun is the case that does.
 @export var garrison_ammo_resource: String = ""
 @export var garrison_ammo_capacity: int = 0
-@export var capabilities: PackedStringArray = []
+# Do not add an explicit `= []` default here. Godot 4.7.1 can discard a
+# PackedStringArray override while converting custom resources to binary .res.
+@export var capabilities: PackedStringArray
 @export var component_scenes: Array[PackedScene] = []
 @export var base_stats: Dictionary = {}
 @export var minimum_stats: Dictionary = {}