RestoreContextOutcome

What restore hands back — the reverse of [RetireContextOutcome], and the same four
fields, plus slug_changed. Restore re-derives the address from the untouched name
rather than trying to recover whatever retire mangled the slug to, so the returned slug
can differ from the one the caller retired under (spec §2.4).

{
    "context_id": "f31d7249-b7b1-4729-b3a4-ec0ba07b4686",
    "context_ref": "string",
    "name": "string",
    "slug": "string",
    "slug_changed": true
}