Fix incorrect JSON source for item_defect_minimum_spacing

[findux]

Read item_defect_minimum_spacing from json_defect instead of json_item.

[fontanf]

Hi,

Thank you for the contribution.

It looks good.

Do you think you could include a unit test by adding corresponding instance/expected solution files like here https://github.com/fontanf/packingsolver/tree/master/data/irregular/tests and adding them as test at the end of this file https://github.com/fontanf/packingsolver/blob/master/test/irregular/irregular_test.cpp ? Otherwise, I'll try to do it myself later

[findux]

Hi,

Thank you for the review.

I can provide the instance JSON file that exposed the issue (the one you shared earlier). instance.json
If needed, I can also help integrate it into the test suite.

Since the change only corrects the JSON source for a single parameter, I wasn't entirely sure how such tests are usually structured in this project. If you prefer to add the test on your side, that would also be perfectly fine for me.

Best regards

[fontanf]

Please integrate the test if you can. As I mentioned above, you just need to solve the problem to get the solution file, store both the instance and the solution files in data/irregular/tests, add the corresponding test at the end of test/irregular/irregular_test.cpp, and run the tests with ctest --output-on-failure --parallel --test-dir build/test/ to check that everything is good. Otherwise, I'll do it myself later