- window.complete() was fire-and-forget, causing execution-complete to arrive before console messages
- This caused sandbox to unregister before console message responses arrived
- Made complete() async and await sendRuntimeMessage()
- SandboxedIframe wrapper now awaits window.complete()
- Ensures all messages are processed before cleanup/unregister
- Fixes 30-second timeout on javascript_repl
5dcb5ecc89