Return why state cannot render as a safe notice, or None when it can.
Collapses the project-then-validate sequence its callers each performed
separately. Their correctness depended on all of them projecting exactly as
the renderer does — the fragility notice_text_sections warns about — so one
implementation is the point rather than the brevity.
Authoritative goal and rubric channels.
Candidate criteria to validate in place of the ones
state projects, for a rubric that is not committed yet. None uses
the projected criteria.
