Qt6 Port and more

[filipestevao]

Hello!

I’m working on a series of updates to bring AlphaPlot up to speed with newer technologies. It’s currently a Work in Progress (Draft), but I wanted to share the progress so far and get some early feedback.

Key Changes:

• Qt6 Port: Full migration from Qt5 to Qt6.
• License Update: Updated from GPL-2.0 to GPL-3.0 for Qt6 compatibility and modern standards.
• Version Bump: Updated the versioning scheme from 1.02 to 1.3.0. This standardizes the format and removes the ambiguity of the leading zero, making the release numbering much clearer.
• AI-Assisted Refactoring: I used AI tools to help with the repetitive parts of the Qt5-to-Qt6 migration. All generated code has been manually reviewed and tested to ensure correctness.
• Flatpak Support: Added compatibility for Flatpak builds.
• Bug Fix: Resolved the auto-resize issue in the last column when "Set Column(s) As" is used.
• Sync: Integrated recent changes from the master branch.

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Why the move to GPL-3.0?

The transition to Qt6 requires updating our licensing to stay compliant with the full ecosystem of libraries and modern FSF recommendations:

1. Qt6 Requirements: Many new add-ons and modules for Qt are strictly available under GPLv3.
2. FSF Recommendations: Version 3 is the current recommendation for updated projects, providing better protections than older versions like LGPLv2.1.
3. Future-proofing: Ensures the project can utilize all future Qt6 features without legal friction.

Sources & Context:

• Qt Open Source Download Page
• KDE Free Qt Foundation
• GPL and LGPL Obligations on Qt.io

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Since this is a draft, feel free to leave any initial thoughts on the architecture, the license change, or the new versioning.

[narunlifescience]

Hi, I’m currently fully occupied with my research work and won’t be able to dedicate time to this project. I’m fine with the license change or version update. Once your work is complete, Just please confirm that it doesn’t break anything and that it has been tested across all three platforms. once that’s verified, I can go ahead and merge it.

[filipestevao]

Hello!

Thank you for the update. I completely understand your focus on your research work.

I’m happy to announce that the work is now complete. I can confirm that everything is working as expected and the migration hasn't broken existing features.

This PR effectively modernizes AlphaPlot’s core with the Qt6 port, updates the license to GPL-3.0, and standardizes the versioning to 1.3.0.

For the upcoming releases, I plan to focus on:

• Wayland Compatibility: Improving support for Wayland environments by migrating from QtDataVisualization to the newer QtGraphs module.
• Fitting Inconsistencies: Addressing bugs related to fitting results, specifically focusing on issue inconsistency in fitting results (error of parameters) when using fit wizard with Custom functions #48 and the report on SourceForge #414.

The PR is ready for your review and merge whenever you have a moment.