[text-channels] Implement WebSocket API for real-time text channel messaging (Backend)

[TheFourthKaramazov]

User Story (Backend)

As a user, I want my messages to be sent and received in a text channel in real time.

Description

The backend should handle WebSocket connections to allow real-time messaging in channels.

Tasks (Backend - FastAPI, WebSockets, SQLite/PostgreSQL)

• Create a WebSocket endpoint for text channel messaging.
• Store messages in the database with sender and channel details.
• Broadcast messages to all users in the channel.

Acceptance Criteria

• Messages are stored with sender and channel details.
• Messages are broadcasted in real time to all users in the channel.
• Users in the channel see new messages instantly.

Priority

High

Labels

• backend
• text-channels
• real-time
• core-feature