Notifications integration: create Notification entries & offline delivery

[mehalyna]

Task 6 — Notifications integration: create Notification entries & offline delivery

Title: notifications: create Notification records on incoming messages and wire offline delivery

Flow

• When a message is created:

  • If recipient(s) connected on socket → message broadcast only.
  • If recipient(s) offline or not focused → enqueue job to create Notification DB record (Postgres) and optionally send email/push.

• Worker behavior:

  • Batch email digests (configurable) or immediate emails (dev console).
  • Add notification rows with type='message', source_user, conversation_id, snippet.

• Implement GET /api/notifications/ and PATCH /api/notifications/{id}/read/ if not present.

Acceptance

• On message to offline user, notification row created and email enqueued (console backend in dev).
• Tests: simulate offline recipient and assert Notification exists.

Dependencies

• Notification model & worker infra (existing).
• Task 3/4 message creation hooks.

Notes

• Respect user notification preferences (if stored). Add opt-out flag to Notification preferences later.