doubles sometimes treated as categories when importing from GraphML

- gephi v1.02
- macos
- chrome v142

I have a graphml file, which has a section describing the keys = for example
````


````

and example values
````
12
12
````
````
0
27
````

When imported they are treated sometimes as categories, and sometimes as numbers

At first I thought perhaps missing values would cause them to be treated as numbers rather than categories, but I have other examples where there are no missing values.

````



````

````
-2
2
4
````

How is it deciding what is a category and what is number ?

Reproduce the GraphML import with the provided key definitions and numeric values, including both the depression and out-degree examples. Trace how imported GraphML attributes are classified as categories or numbers, then define the expected classification for declared double attributes and verify it against both examples.

Written by the indexing model from the issue text.