Explore how to handle traget type sizes (e.g. Long) separately from modeling concerns

[strangemonad]

May have some overlap with #1 (e.g. how the largest representable int in a 64 bit long implicitly constricts the type of ints).

This should be a separate issue from having to specify an int64 in the model - i.e. only use an int64 if you’re modeling something that has byte size / packing concerns (e.g. modeling a network packet).

[strangemonad]

There is some overlap with how the swift ABI must consider function signature lowering