Show friendly message when opening sessions created by another client

Description

Sessions are shared across Claude Code clients (CLI, VSCode extension, Desktop app, Web) via ~/.claude/, so they all appear in the session list regardless of where they were created. However, when you try to open a session that was created by a different client, you get a cryptic error:

Error: Query closed before response received

This gives no indication of what went wrong.

Expected behavior

Instead of an error, show a clear message like:

"This session was created in [Desktop/CLI/Web] and cannot be opened here."

Or hide/gray-out sessions that aren't compatible with the current client.

Steps to reproduce

1. Create a session in Claude Desktop app
2. Open Claude Code in VSCode extension (or vice versa)
3. Find the session in the session list and try to open it
4. Observe the error message

Environment

• macOS Darwin 25.6.0
• Claude Code VSCode extension
• Sessions originally created in Claude Desktop app