CVE-2026-65965: ideon: Read-only project viewers can wipe and rewrite the canvas and tamper with blocks/files via role-unchecked project endpoints

ideon is a self-hosted visual workspace. Prior to version 0.9.4, several project mutation endpoints under /api/projects/[id]/ resolve the caller's project role but never enforce it, so a user who was granted only the read-only viewer role on a project can perform write operations on that project. The most severe is POST /api/projects/[id]/graph, which deletes every block and link in the project and re-inserts client-supplied ones. A viewer can silently rewrite or wipe the entire canvas of a project they were invited to read. The application clearly intends viewer to be read-only: the collaborators endpoint, the automation endpoints, and the realtime Yjs sync path all reject write attempts from viewers. These specific HTTP handlers simply omit the guard their siblings enforce. This issue has been patched in version 0.9.4.