GET /v3/instruments/:id

Fetch one instrument by ID.

Path params:
  id (required) — Instrument identifier (Mongo ObjectID).

Response (200 OK):
{
  "data": {
    "id": "string",
    "type": "<one of the instrument types — see /v3/instruments>",
    "attributes": { /* type-specific — see the per-type spec page */ },
    "relationships": { /* type-specific where applicable */ }
  }
}

To learn the per-type schema, use:
  aleta api --spec POST /v3/instruments --type bond-instrument
  aleta api --spec POST /v3/instruments --type stock-instrument
  ...
The GET response shape mirrors the POST request shape for the same type.