Add Troubleshooting for Common QT Issues

[seanpearsonuk]

• Add a new section in the documentation: “Troubleshooting PyFluent Visualization in Notebooks and IDEs”.
• The following may not be accurate or complete (it is LLM generated).
• Include common causes for ImportError due to mixed QT bindings.
• Suggest best practices:
  • Don’t mix PyQt5 and PySide6.
  • Use clean virtual environments.
  • Run GUI code outside of IPython if needed.
  • How to check current QT backend.
• Include a known-issues section specifically for Spyder, JupyterLab, VSCode.