Feature: Attach to running Claude Code process for remote monitoring

Summary

Add the ability to attach to a running Claude Code process from another location, enabling remote monitoring and interaction with an ongoing session.

Use Case

I start working on a task locally with Claude Code, then need to leave my workstation. I would like to:

1. Monitor the progress of the running session from another device (e.g., phone, laptop)
2. Continue interacting with the same conversation remotely
3. Return to my local workstation later and reconnect to the same session

Current Limitation

Currently, each Claude Code invocation creates a new conversation. If I start work locally, there's no way to:

• Monitor that session's progress remotely
• Continue the same conversation from a different device
• Attach to the running process without interrupting it

Proposed Solution

Add a mechanism to attach to a running Claude Code process, similar to how tmux attach or screen -r work for terminal sessions. This could work by:

1. Session persistence: Running sessions generate a unique session ID
2. Remote attach: A command like claude --attach <session-id> connects to the running session
3. Multi-client support: Multiple clients can observe/interact with the same session
4. Graceful handoff: Original process can continue running while remote client attaches/detaches

Alternative Approaches

• Web-based session viewer (similar to how this Telegram bridge works)
• Cloud-synced session state with resume capability
• Integration with existing remote access tools

Benefits

• Better workflow continuity when moving between devices
• Ability to monitor long-running tasks remotely
• Improved collaboration (multiple people can watch/participate in same session)
• More seamless integration with mobile workflows

Related

This feature would complement the existing --resume functionality, which resumes a completed session, by allowing attachment to an in-progress session.