This is a serious tripping point with Go. There's no way to express: "this is a root context that I _want_ to store and only use to create derived contexts". Goroutines are also a source of problems, you can't easily say "I'm passing the ownership of this context to a goroutine".
I took a quick look at "containedctx" and it seems like for this case, it would almost be backwards: it would flag the (not-memory-leaking) struct-stored "status.ctx", but wouldn't flag when there is a stored "status.cancelFn" only (which resulted in the memory leak).
Could Go implement a runtime leaked-context detector, like the data race detector? https://go.dev/doc/articles/race_detector
In this case, the cancel() function was preventing the collection. But I think it can be changed to hold a weak reference instead. The overhead is too large to run it normally, but it should be OK for something like the race detector.