CVE-2026-61596: djust has broken object-level access control (IDOR)

djust’s per-object authorization (get_object + has_object_permission, ADR-017) was enforced on the WebSocket mount and event paths but not on three other render entry points: (a) the initial HTTP GET render, (b) SPA url_change navigation, and (c) {% live_render %} embedded child views. An authenticated user could therefore view (and on some paths act on) an object they are not authorized for by loading the page directly, navigating to it via SPA url-change, or composing it as an embedded child — a classic IDOR / broken object-level access control on object-scoped views.