Get a thread

{  "assistant_id": "a1b2c3d4-5678-9abc-def0-1234567890ab",  "created_at": "2025-03-15T09:12:33.456789Z",  "id": "1a2b3c4d-5678-9abc-def0-112233445566",  "last_updated_at": "2025-03-15T09:45:12.123456Z",  "tenant_id": "abcd1234-ef56-7890-abcd-ef1234567890",  "title": "Kündigung während der Probezeit",  "user_id": "f8e7d6c5-4321-fedc-ba98-765432109876"}

{  "error_code": "thread_is_deactivated",  "detail": "Thread is deactivated"}

{  "error_code": "unauthorized",  "detail": "Missing or invalid API key"}

{  "error_code": "thread_not_found",  "detail": "Thread not found"}

{  "detail": [    {      "loc": [        "string"      ],      "msg": "string",      "type": "string",      "input": null,      "ctx": {}    }  ]}

{  "error_code": "internal_server_error",  "detail": "Internal Server Error"}