// EmitterBox — thin wrapper to emit JSON v0 (extracted)
box EmitterBox {
  emit_program(json, usings_json) {
    if usings_json == null { return json }
    // Attach meta.usings when available and non-empty (bridge ignores unknown fields)
    if usings_json.length() == 0 { return json }
    if usings_json == "[]" { return json }
    // naive injection: insert before the final '}' of the top-level object
    local n = json.lastIndexOf("}")
    if n < 0 { return json }
    local head = json.substring(0, n)
    return head + ",\"meta\":{\"usings\":" + usings_json + "}}"
  }
}

static box EmitterStub {
  main(args) { return 0 }
}