CVE-2026-86085: n8n: Cross-Tenant Project-Member PII Disclosure via Missing Per-Project Scope Check on Role Assignment Endpoints

The endpoints /rest/roles/:slug/assignments and /rest/roles/:slug/assignments/:projectId/members checked only that the caller could manage the role type, not that they could see the project named in the request. A user holding role-management permission could therefore name any project on the instance and read back its members’ names and email addresses. The patch adds a project-access check to both routes, hiding projects the caller cannot see and returning not-found for a project it cannot list.