Feature/client event handling

[Rishygunjal]

Channel Event Enhancements

@Abhishekvrshny I have made changes so that I can send channel events both to other clients as well as to backend services.

---

1. Client → Backend

• When a client sends a channel event, the backend must be subscribed to the specific topic mentioned in the channel_event payload.
• Once subscribed, the backend can immediately start listening to events on that topic.
• I have also created a sample backend.go file that demonstrates how this can be used.

Sample channel_event payload

{
  "channel_event": {
    "event": {
      "data": {
        "type_url": "minim irure ullamco dolore",
        "value": "Ns6="
      },
      "format_type": "TYPE_JSON_UNSPECIFIED",
      "name": "anim ea"
    },
    "topic": "qui aute", //Topic name should be mentioned here
    "unique_id": "reprehenderit"
  }
}

2. Client → Client

• I have added functionality that automatically forwards channel events to other clients.
• Similar to the backend case, the receiving client must have subscribed to the topic mentioned in the channel_event payload.
• For now, inter-client communication works only on a topic-based model.
• In the future, we can extend this to support other routing options such as:
  • client device IDs,
  • multiple topic subscriptions,
  • or hybrid approaches (topic + device ID).

💡 Idea Credit

This idea was discussed and worked on by me and @jaig10 . Together we explored how event handling can be extended in Propeller, and this draft PR represents our joint contribution.