Frequency values are not consistent in format

[szporwolik]

The returned format of the frequency is not consistent, depending on the spot source - cluster vs POTA, the frequency is returned as string or number.

This is not a big thing, but may cause some troubles in integration.

Example (see frequency value - returned today from jo30 instance)

  {
    "spotter": "IV3IDO",
    "spotted": "II3GONG",
    "frequency": 28500,
    "message": "european city of culture 2025",
    "when": "2025-11-11T15:40:08.722Z",
    "source": "cluster",
    "dxcc_spotter": {
      "cont": "EU",
      "entity": "Italy",
      "flag": "🇮🇹",
      "dxcc_id": "248",
      "lotw_user": "271",
      "lat": "41.9",
      "lng": "12.5",
      "cqz": "15"
    },
    "dxcc_spotted": {
      "cont": "EU",
      "entity": "Italy",
      "flag": "🇮🇹",
      "dxcc_id": "248",
      "lotw_user": "8",
      "lat": "41.9",
      "lng": "12.5",
      "cqz": "15"
    },
    "band": "10m"
  },
  {
    "spotter": "N9ANA",
    "spotted": "N9ANA",
    "frequency": "21063.5",
    "message": "CW POTA @ US-12184 Heidecke Lake State Fish and Wildlife Area (US-IL)",
    "when": "2025-11-11T15:41:08.737Z",
    "source": "pota",
    "dxcc_spotter": {
      "cont": "NA",
      "entity": "United States Of America",
      "flag": "🇺🇸",
      "dxcc_id": "291",
      "lotw_user": "871",
      "lat": "43",
      "lng": "-87.9",
      "cqz": "5",
      "pota_ref": "US-1024",
      "pota_mode": "CW"
    },
    "dxcc_spotted": {
      "cont": "NA",
      "entity": "United States Of America",
      "flag": "🇺🇸",
      "dxcc_id": "291",
      "lotw_user": "871",
      "lat": "43",
      "lng": "-87.9",
      "cqz": "5",
      "pota_ref": "US-1024",
      "pota_mode": "CW"
    },
    "band": "15m"
  },