Omit project_role no longer defaults to member. Exclusive duty writes
take an advisory lock and retry conflicts so last-writer wins without
dual reviewers. Author write tests require err==nil.
Co-authored-by: Cursor <cursoragent@cursor.com>
Stop inventing reviewer_id=2. Use project document_duty as the authority, heal missing or non-member placeholders, and keep write paths rejected for reviewer and outsiders.
Co-authored-by: Cursor <cursoragent@cursor.com>