Working Leo composition note. A newly captured document may produce claim and evidence candidates, but those candidates are not canonical knowledge. A staged proposal remains non-canonical until an operator reviews it and a separate guarded apply succeeds. The proposal must retain the source content hash, exact evidence excerpt, and source identity so reviewers can trace every planned row back to the captured artifact. For a staging-only rehearsal, pending_review is the terminal state. No public knowledge-base row should be written.