All cross-service events now flow through ap_activities with a unified EventProcessor. Internal events use visibility="internal"; federation activities use visibility="public" and get delivered by a wildcard handler. - Add processing columns to APActivity (process_state, actor_uri, etc.) - New emit_activity() / register_activity_handler() API - EventProcessor polls ap_activities instead of domain_events - Rewrite all handlers to accept APActivity - Migrate all 7 emit_event call sites to emit_activity - publish_activity() sets process_state=pending directly (no emit_event bridge) - Migration to drop domain_events table Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>