Support real-time watch mode and enable auto-response for specific chatrooms

[channprj]

Summary

We need to implement a "watch mode" that streams messages from a specific KakaoTalk chatroom and enables automated responses based on those messages.

Proposed Features

• Watch Mode (Streaming): Continuously monitor and stream new messages from a designated chatroom.
• Message Parsing: Real-time extraction of message content, sender information, and timestamps.

Expected Usecases

• kmsg read --chat_id=123 --watch
• kmsg watch --chat_id=123

Additional Contexts

• User can automatically sends a pre-configured response to that chatroom immediately.
• User can integrate LLM and MCP to enable context-aware, intelligent automated responses via kmsg.