refactor: Extract messages + notifications blueprint (Phase 4)
- Create blueprints/messages/ with 11 routes:
- messages_inbox, messages_sent, messages_new, messages_send
- messages_view, messages_reply, api_unread_count
- api_notifications, api_notification_mark_read
- api_notifications_mark_all_read, api_notifications_unread_count
- Register messages blueprint with backward-compatible aliases
- Remove dead code from app.py (-340 lines)
- app.py: 13,398 → 13,058 lines (-2.5%)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Maciej Pienczyn
0f482cc4aa