Reads the effective RealtimeModeratorConfig from a resolved config, filling absent fields from
REALTIME_MODERATOR_DEFAULTS. Returns null when no moderator is configured at all (e.g. no
promptId), which the engine treats as "no moderator — fall back to per-agent matchers".
Reads the effective RealtimeModeratorConfig from a resolved config, filling absent fields from REALTIME_MODERATOR_DEFAULTS. Returns
nullwhen no moderator is configured at all (e.g. nopromptId), which the engine treats as "no moderator — fall back to per-agent matchers".