Add ARFCN field support to termux-telephony-cellinfo

[muojp]

Adds E-ARFCN and NR-ARFCN field output to enable more accurate cellular signal frequency analysis and debugging.

Changes:

• Add E-ARFCN field for LTE cells (API level 24+)
• Add NR-ARFCN field for 5G NR cells
• Both fields provide absolute radio frequency channel numbers for precise frequency identification

[muojp]

Sample output taken from actual test run on my device:

~ $ termux-telephony-cellinfo 
[
...
  {
    "type": "lte",
    "registered": false,
    "asu": 33,
    "dbm": -107,
    "level": 1,
    "pci": 158,
    "rsrp": -107,
    "rsrq": -18,
    "rssi": -77,
    "bands": [
      1
    ],
    "arfcn": 500
  }
]

[bankz1990]

E-ARFCN

[muojp]

@bankz1990 yes, E-ARFCN! Any feedbacks or suggestions? I'd love to get feedbacks!