POST /v2/legal-entities/:id/depositories

Create a depository under a legal entity.

Path params:
  id (required) — Legal-entity identifier.

Request:
{
  "data": {
    "type": "depository",
    "attributes": {
      "name":               "string (optional)",
      "externalIdentifier": "string (required) — bank/custodian-assigned identifier"
    }
  }
}

Response (201 Created):
{
  "data": {
    "id": "string",
    "type": "depository",
    "attributes": { /* same as request */ },
    "relationships": {
      "legalEntity": { "data": { "type": "legal-entity", "id": "string" } },
      "accounts":    { "data": [] }
    }
  }
}