ION Scripts require fixed variable names (data_in / data_out)

[theblackapple5150]

ION scripts currently require the input variable to be named data_in
and the output variable to be named data_out.

Any other variable causes the script to fail.

Scripts should either:

1. Support dynamic input/output variable names, OR
2. Provide clear validation/error messaging when incorrect names are used

Current Behavior:

• Scripts fail or behave unexpectedly when using custom variable names

This is a usability limitation and can be confusing if not known.
Improving this would make scripts more flexible and easier to adopt.