Follows the portal: the noun is "instance" everywhere the app says it —
UI strings, CLI output, error details, docs and comments. The wire keys
(`instance_id`, `instance_token`) and the hub route this calls move with it.
An existing cloud.json is adopted rather than refused: without the key
alias the dataclass fails to parse, which the caller swallows and reads as
"never enrolled" instead of "reconnect".
`instance_key` on a node type becomes `target_key`. It means the outside
thing a node points at, which is a different sense of the word, and keeping
both would put two meanings of "instance" in one codebase.
The app said things in two places: sonner's bottom-right toasts and the
custom top-centre chrome. This is the second of those, generalised — a
module-level store anyone can call, drawn as a stack of frosted cards that go
on their own unless raised as persistent, with room for buttons and for a
message longer than a line.
useCustomToast keeps its signatures, so the forty-odd call sites behind it and
handleError are untouched. The component and its store are byte-identical with
the portal's copy and checked by `make design-check`.