SG-40980 Add support for VFX CY2026 - Python 3.13 - Qt 6.8

[julien-lang]

This PR adds compatibility with VFX CY2026 by updating the README badges to reflect support for:

• Python 3.9 through 3.13
• Qt 5.15 through 6.8
• PySide2 2.0 through PySide6 6.8

[Copilot]

Pull request overview

This PR adds support for Python 3.13 by updating CI configuration, documentation badges, and error messaging to reflect the updated Python and Qt library support.

• Updates CI pipeline to use a branch with Python 3.13 support
• Updates README badges to include Python 3.13 and VFX Platform CY2026
• Updates error message to reference PySide6 instead of PyQt

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
azure-pipelines.yml	Updates CI template reference to ticket branch for Python 3.13 support
README.md	Updates badges to reflect Python 3.13 and VFX Platform CY2026 support
engine.py	Updates Qt library reference in error message from PyQt to PySide6

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.82%. Comparing base (fff71b7) to head (9700d56).
⚠️ Report is 10 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #37      +/-   ##
==========================================
+ Coverage   74.66%   74.82%   +0.16%     
==========================================
  Files           4        4              
  Lines         150      147       -3     
==========================================
- Hits          112      110       -2     
+ Misses         38       37       -1     

Flag	Coverage Δ
Linux	74.82% <ø> (?)
Python-3.10	74.82% <ø> (?)
Python-3.11	74.82% <ø> (?)
Python-3.13	74.82% <ø> (?)
Python-3.9	74.82% <ø> (?)
Windows	74.82% <ø> (?)
macOS	74.82% <ø> (?)

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