[Bug] Sandbox unavailable error when sandbox.failIfUnavailable is enabled

Bug Description
When we try to continue a previus version session with claude --continue we get
9248: Error: sandbox required but unavailable: ${j$}
9249: + sandbox.failIfUnavailable is set \u2014 refusing to start without a working sandbox.

Environment Info

• Platform: linux
• Terminal: tmux
• Version: 2.1.120
• Feedback ID: 46ef958c-9aea-4872-8709-ddf07c966a1e

Errors
9248: Error: sandbox required but unavailable: ${j$}
9249: + sandbox.failIfUnavailable is set \u2014 refusing to start without a working sandbox.