* fix: ensure `$state.snapshot` never errors
Snapshotting can error on un-cloneable objects. It's not practical to error in this case; often there's no way out of this for users, so it makes sense to return the original value in that case, and warn in dev mode about it.
closes#12438
* lint
* single warning per snapshot call, list affected properties
* lint
* lint
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Co-authored-by: Rich Harris <rich.harris@vercel.com>
Simon H