Set dynamic worker executor timeout to 60 seconds

[mattzcarey]

Summary

• add a 60 second timeout guard around dynamic Worker execute code evaluation
• surface a clear timeout error when sandboxed code runs longer than the configured limit
• cover the default timeout and timeout behavior in executor tests

Testing

• npm run check

[mattzcarey]

Closing per request; we'll revisit whether this should use the Code Mode SDK dynamic worker executor instead.