Implement "Show 'typing...' status" in Chat Rooms

[iammuho]

Implement a real-time update system to notify all users in a chat room when someone starts or stops typing. The feature will be implemented using a POST API endpoint and WebSocket notifications.

Requirements:

• API Endpoint: Create a new POST API endpoint /room/:roomID/event for the typing event. This endpoint will accept an eventType to indicate whether typing has started or stopped.

Sample API Contract:

POST /room/:roomID/event { "eventType": "typing.started" }

• Event Types: Two event types should be supported:

EventTypeTypingStart ("typing.started"): User has started typing.
EventTypeTypingStop ("typing.stopped"): User has stopped typing.

• WebSocket Notification: Once the server receives the API request, it should broadcast this event to all users in the room using WebSockets.
• Rate Limiting: Implement rate limiting for this feature to avoid unnecessary network calls. For example, limit the number of "typing started" and "typing stopped" events per user per second.

Success Criteria:

• Users in the same room should see real-time updates when someone starts or stops typing.
• The feature should be resilient and optimized, adhering to best practices.

[iammuho]

PR is created, waiting for some review: #28