Put people into a sequence

Enrolls contacts at the sequence's first step — and WRITES their messages: every step's email or LinkedIn note is written per person at enrollment (entries inline, the rest within minutes), stored per step, editable via the messages endpoints before anything is live. A draft or paused sequence enrolls fine; its first messages park in the review queue and nothing sends until it is turned on. **Sending uses the caller's own connected mailbox** — `enrolled_by` comes from the session, never a colleague's. Idempotent: somebody already moving through the sequence is left exactly where they are; somebody who finished is put back at the start; somebody unreachable on every channel is skipped and named in the response.

curl -X POST "https://loading/api/v1/org/sequences/497f6eca-6276-4993-bfeb-53cbbbba6f08/enrollments" \  -H "Content-Type: application/json" \  -d '{    "org_contact_ids": [      "497f6eca-6276-4993-bfeb-53cbbbba6f08"    ]  }'

{
  "data": {
    "enrolled": -9007199254740991,
    "alreadyIn": -9007199254740991,
    "restarted": -9007199254740991,
    "unreachable": [
      "string"
    ],
    "drafted": -9007199254740991,
    "searching": [
      "string"
    ]
  }
}

{
  "error": "string",
  "message": "string",
  "statusCode": -9007199254740991
}

{
  "error": "string",
  "message": "string",
  "statusCode": -9007199254740991
}

{
  "error": "module_required",
  "module": "string",
  "message": "string",
  "contact": "string"
}

{
  "error": "string",
  "message": "string",
  "statusCode": -9007199254740991
}

{
  "error": "string",
  "message": "string",
  "statusCode": -9007199254740991
}