issue list/show/create/update, version list/create, category
list/create, relation create. Names resolve case-insensitively against
server enumerations; -o json everywhere; exit 0/1/2 with one-line
stderr carrying the http status for API failures.
Issues (create/update/partial PUT, notes-as-journals), versions,
categories, relations, and name-to-id resolution over trackers/
statuses/priorities. Sentinel errors carry http codes one-line; response
bodies are never surfaced so the API key cannot leak through error
strings (the fake deliberately echoes the presented key to prove it).