fix: reference-geometry parameter not working with upper/mixed case secondary instance names

[lindsay-stevens]

Fix for bug report in https://forum.getodk.org/t/58592
Test to more clearly document duplicate ref-geo behaviour per https://forum.getodk.org/t/57427/51

Why is this the best possible solution? Were any other approaches considered?

Expanded list of case-sensitive parameter names to include reference-geometry, so it can match any valid secondary instance name. Added tests to cover lower/upper/mixed case names for each output test case, to avoid regressions. Replaced original parameter name list with references to the param names, and added comment, to make it more obvious how they are related.

With these changes, the repro XLSForm provided in the forum thread converts without errors or warnings: input Reference geometry error.xlsx result Reference geometry error.xml.

What are the regression risks?

Should be none - this was a bug blocking upper or mixed case secondary instance names.

Does this change require updates to documentation? If so, please file an issue here and include the link below.

No

Before submitting this PR, please make sure you have:

• included test cases for core behavior and edge cases in tests
• run python -m unittest and verified all tests pass
• run ruff format pyxform tests and ruff check pyxform tests to lint code
• verified that any code or assets from external sources are properly credited in comments

[lognaturel]

Nice! Thanks for getting right on that.