Users can message other users

[bilalAhmadAyoub]

Estimate: 1 day

As a user,
I want to privately message other users,
so that I can confirm details like pick-up location and time.

Acceptance Criteria
Scenario: User sends a private message to another user
Given that I am logged in and viewing another user’s post
When I click the "Message" button
Then the system opens a private chat window with that user
When I enter a message and click "Send"
Then the system sends my message to the recipient
And the recipient receives a notification of my message.