Description

This PR delivers the backend support required for handling non‑public pages within menu structures.

It includes the following:

Updated PageLink.get_api_representation to:

• Evaluate page visibility using check_permissions
• Include only pages the user is authorised to access
• Remove non-public pages from the response if the user lacks permission
• Remove all non-public pages when there is no authenticated user

Fixes #CDD-3441

Type of change

Please select the options that are relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Tech debt item (this is focused solely on addressing any relevant technical debt)

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests at the right levels to prove my change is effective
• I have added screenshots or screen grabs where appropriate
• I have added docstrings in the correct style (google)