Anonymous read of a brief that has been explicitly published.

Lookup is keyed on (id, is_public=true), so unpublished briefs return 404 even with a valid id — no signal leaks about whether the id maps to a real-but-private brief. Output is filtered through the existing "full" access tier so promoter viewers see pricing, risk_output, and revenue, but identity fields (user_id, team_id, langsmith_run_id, agent_errors) are stripped before responding.