Preview effective permissions

Merges permissions from a list of role IDs. Authenticated users can call this endpoint (no extra permission annotation).

Request

POST /permissions/preview

Header	Value
`Authorization`	`Bearer <token>` (or HMAC headers, see Authentication)
`Content-Type`	`application/json`

A JSON array of Auth0 role IDs.

["rol_abc123", "rol_def456"]

Deduplicated permission strings. Count is in X-Total-Count.

[
  "usermanagement.read",
  "pageeditor.read",
  "search.read"
]