- SCHEMA-03: content.add now writes DWN file-catalog/v1 message alongside the existing catalog entry. File metadata queryable via dwn.query-messages. - SCHEMA-04: federation.join now writes DWN federation/v1 membership message. Federation relationships queryable via DWN protocol filter. Both integrations are non-fatal on DWN errors (existing flows unaffected). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>