Identifiy and fix broken cron workflows

We have a problem where empty cron workflows recurse forever - see https://github.com/OpenFn/kit/issues/1367

I have put a bandaid on the problem for new workflows. But existing ones may still give us problems.

This issue is two-fold:

1. identify any existing workflows on prod and staging which may trigger this behaviour
2. roll out a fix

Identification

We need to work out which workflows are affected.

These things must be true:

• The workflow must be on a cron trigger
• The workflow must have empty bodies (empty is not nil, it could just mean a comment)
• The workflow must have multiple leaf nodes. Probably not enough to just have true/false branches - it's gotta have true/true edges

I don't know which of these we can use to build a query - some of them are quite hard heuristics

What might help is: the worker will detect runs with multiple leaf nodes. If a run does NOT have multiple leaves, it'll include final_dataclip_id. So maybe: identify cron runs which did not return final_dataclip_id in the final payload - those are the ones we need to fix.

For the record, this affects at least one workflow on prod: https://app.openfn.org/projects/57862287-23e6-4650-8d79-e1dd88b24b1c/w/0f1d0b6e-8426-4023-959d-a89ba824f3c0

Fix

Consider the following:

• Edit the last dataclip - the source for the next cron - to be an empty object {}
• Delete or edit prior dataclips, which could be taking up a lot of storage and providing no value
• Disabling the cron trigger (bear in mind that if a user switches it back on, they'll just provoke the problem again)

When deciding how aggressively to fix this, we need to consider if we're looking at demo code or a real project.

Start by reading the worker behavior described in OpenFn/kit#1367 and inspect cron runs whose final payload lacks final_dataclip_id. Identify affected workflows on production and staging using the listed trigger, empty-body, and multiple-leaf criteria; done means affected workflows are found and their dataclips or cron triggers are safely fixed.