Update GzSpinBox to use the SpinBox QML module from QtQuick.Controls2

[azeey]

Toward #586

Summary

The SpinBox module from QtQuick.Controls1 has been deprecated in Qt5 and removed in Qt6. The new SpinBox has a different API and does not directly support floating point values. The workaround in this PR is to store the floating point numbers in a fixed-point representation.

The implementation was inspired by the example in https://doc.qt.io/qt-5/qml-qtquick-controls2-spinbox.html

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.72%. Comparing base (8edf24d) to head (c0aa01e).
Report is 11 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #654      +/-   ##
==========================================
+ Coverage   68.49%   68.72%   +0.23%     
==========================================
  Files          38       38              
  Lines        5567     5544      -23     
==========================================
- Hits         3813     3810       -3     
+ Misses       1754     1734      -20     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[iche033]

code changes look good to me.

I noticed an issue that when expanded the - button overlaps with the display text:

Also not sure if it's possible to make the - and + buttons a different background color from the display text field (something like the screenshots in https://doc.qt.io/qt-5/qml-qtquick-controls2-spinbox.html). At first glance, the - button makes it look like the spinbox contains a negative number.

[azeey]

code changes look good to me.

I noticed an issue that when expanded the - button overlaps with the display text:

Also not sure if it's possible to make the `-` and `+` buttons a different background color from the display text field (something like the screenshots in https://doc.qt.io/qt-5/qml-qtquick-controls2-spinbox.html). At first glance, the `-` button makes it look like the spinbox contains a negative number.

I've addressed your feedback in 7330c06 and actually got it to look like the SpinBox from the previous version.

8eae434 cleans up some warnings related to bindings.

[iche033]

nice, works well for me