Create Stream Replay Buffer

[Mosas2000]

## Description

Buffer recent real-time events so disconnected clients can replay missed updates after reconnecting.

## Requirements and context

- Bounded event storage

• Replay by topic

• Sequence tracking

• Expiration policy

• Reconnect support

• Metrics output

  Suggested execution

  Fork the repo and create a branch

  git checkout -b feature/backend-stream-replay

  Implement changes

  • Create replay buffer service

• Integrate with websocket delivery

• Expose replay endpoints

• Document replay semantics

  Example commit message

  feat: create stream replay buffer

  Guidelines

  • Assignment required before starting
  • PR must include a closing reference to this issue
  • Include screenshots or examples where applicable
  • Timeframe: 72 hours