Chat Service MVP

Implement basic 1-on-1 chat with a manager (logic may evolve):

• Chat initiated from client
• Messages go to one assigned assistant

📋 Acceptance Criteria

✅ What to consider:

• Messages must be sent and received in real-time or near real-time.
• All messages should be stored persistently and displayed in the correct order.
• The chat UI should update automatically when new messages appear.

✅ Acceptance Criteria (AC):

• GIVEN a user enters the chat

• WHEN they send a message

• THEN the message is stored and immediately appears in the chat window

• GIVEN a user enters the chat

• WHEN they receive a message

• THEN the message is displayed in the correct position in the conversation

• GIVEN the chat is active

• WHEN multiple messages are exchanged

• THEN the message history is preserved and all messages are shown in chronological order

✅ Please check the Definition of Done before moving this issue to Close.