Plan approval from web app not registering when multiple sessions/devices open simultaneously

Description

When a plan approval is submitted via the Claude Code web app, the approval does not register if the same session is open on multiple devices simultaneously.

Steps to Reproduce

1. Start a Claude Code session with a long-running task that presents a plan for approval
2. Have the web app open on 2+ devices at the same time
3. Approve the plan on one device
4. Observe: the session remains stuck at the approval prompt, not proceeding

Expected Behavior

Approving the plan on any connected device should cause the session to proceed with execution.

Actual Behavior

The session stays frozen at the plan approval prompt. The approval appears to complete on the client side but the backend session does not advance.

Environment

• Claude Code web app (preview)
• Multiple devices connected to the same session simultaneously
• Remote session running in a tmux session on a headless Ubuntu 24.04 VM

Notes

This is likely a multi-client/session sync issue. The approval event may not be propagated correctly to the active session when multiple clients are attached. Given this is a preview product, flagging for awareness.