Review fixes:
- mark_all_read now filters status IN (sent, delivered), preventing
pending notifications from being incorrectly marked as read
- schedule_notification tool: force UTC on naive datetimes, reject
past dates (send immediately instead)
- WebSocket notification payload now includes all fields matching
NotificationResponse (user_id, channel, status, scheduled_at, etc.)
- Centralized _serialize_notification helper in notification_sender
- notification_sender: per-notification error handling with rollback
- health_review: moved import json to module top level
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
dolgolyov.alexei
04e3ae8319