First-pass JSON diff: test the comparison semantics

Before diffing large JSON files, compare two small safe objects that differ in key order, array order, null versus missing, and a string-versus-number value. Observe which changes the tool reports. Key order usually does not alter object meaning, while array order and types often do. Once the behavior is clear, compare the real documents and validate the result against its schema. A tool's display setting can otherwise hide the exact change you care about.