Vikunja has an incomplete fix for CVE-2026-35595: Write-only user can detach shared project from parent hierarchy via parent_project_id=0

Summary The fix for CVE-2026-35595 project re-parenting privilege escalation only gates reparent operations when parentprojectid 0. A user with Write but not Admin permission on a shared child project can detach it from its parent by sending parentprojectid: 0, bypassing the Admin requirement. Th...