[N-EMIT1] Define notification emitters for events (reflow, node join, proposed answer lifecycle, termination, chat message)

[zhn1010]

Priority: High
Type: Logic design
Est: 2h
Original Ref: N-EMIT1

[vedadian]

In case of occurrence of these events, corresponding notifications must be published:

• ReFlow: No notifications for now
• Node Joined:
  1. Notify parent node that the link they shared has resulted in the invitee to join the quest
  2. Notify the seeker that the quest's share tree has expanded
• Terminated: Notify all nodes that the quest has terminated, include farewell message
• Expired: Notify all nodes that the quest has expired, there is no "farewell message" :(
• Answer Accepted: Notify all nodes that the quest has succeeded, include farewell message. For the winning branch, the text must be informative of the winning and include a "congratulations" phrase. It also has to include the reward amount for the specific node.
• Answer Proposed: Notify the seeker that a new lead has been submitted
• Comment Added: Notify the seeker that there is a new incoming comment
• Quest Edited: No notifications for now
• New Chat Message: Must notify the recipient that he/she has an unread message. Obviously for messages that are immediately received by the recipient, no notifications must be published (It is preferable to aggregate closely timed unread message notifications into a single notification)