Add TIMELINE_EVENT_NOT_FOUND (404), TIMELINE_EVENT_CONFLICT (409), TIMELINE_TITLE_TOO_LONG (400), and a generic CONFLICT (409) used by the optimistic-lock backstop. Per #775 / ADR-040. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Add TIMELINE_EVENT_NOT_FOUND (404), TIMELINE_EVENT_CONFLICT (409), TIMELINE_TITLE_TOO_LONG (400), and a generic CONFLICT (409) used by the optimistic-lock backstop. Per #775 / ADR-040. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>