Configures the probe task before it is launched: how it blocks, for how long, and the input value its function reads.

Lets every invocation of the function return.

Stops the running task and launches a NEW node in its place, in one callback. m.top.task then holds the new node; the stopped one is returned so the spec can still read it.

The app's sequence: STOP, then launchTask, with nothing in between.

The app's full sequence, which is not just STOP-then-launch: every site writes its INPUT field between the two (m.searchTask.query = query, m.loadDetailsTask.itemId = itemId). That write is why an ignored relaunch can still look right — the old run, if it survives, reads the new value.