A per-corpus skill copies this directory and fills every <PLACEHOLDER>. None of
them has a default: a corpus's budget, instrument, profile name and conditional
fields are facts about that corpus, and a default would be this repository
asserting one it has not measured.
The section headings are fixed because the checker in the next commit reads
them by name. references/example-payload.json is the known-positive that keeps
a refuse-everything checker from passing.
