feat: add NMAxe miner family driver support

[aetherwraith]

Summary

This PR adds official driver support for the NMAxe family of home miners running the ESP-Miner-NMAxe (AxeOS) firmware (NMAxe, NMAxeGamma, and NMQAxe++).

Key Features Implemented:

1. Telemetry parsing: Reads /api/system/info which maps nested sub-objects (power, temps, asic, miner, identity, fans, stratum) to the standard MinerSample object.
2. Frequency and Voltage Control: Support for hot-applying core voltage and frequency settings via /api/setting/mining (asicVcoreReq / asicFreqReq).
3. Fan Controls: Sets speed percentage and toggles automatic/manual mode via /api/setting/preference for all active fan indexes (single fan on NMAxe/Gamma; dual fans on NMQAxe++).
4. Pool Configuration: Reads and saves primary/fallback stratum configs via /api/setting/mining (handling full stratum URLs with schemes).
5. Reboot and Pause/Resume Support: Triggers a graceful reboot via /api/system/restart, and implements runtime pause/resume control via PATCH /api/mining/state (can_pause = True).
6. Autodetect Discovery: Added NMAxe detection to /api/discovery (classified by the presence of nested identity blocks).
7. Comprehensive Unit Tests: Added unit tests covering all NMAxe driver behaviors (parsing, controls, pause/resume, and pool config).

Checklist:

• Compilation sanity checks passed (python -m py_compile ...)
• No personal credentials or LAN data committed
• README table and description updated
• CHANGELOG entry added under [Unreleased]
• Tested against the full project test suite (all 237 tests pass)

Raw /api/system/info Payload Sample:

{
  "power": {
    "power": 12.5,
    "vbus": 5000,
    "ibus": 2500
  },
  "temps": {
    "vcore": 45.2,
    "asic": 62.7
  },
  "asic": {
    "count": 1,
    "model": "BM1370",
    "vcoreReq": 1200,
    "vcoreReal": 1198,
    "freqReq": 490,
    "smallCoreCnt": 672
  },
  "miner": {
    "state": "running",
    "paused": false,
    "pauseReason": "",
    "hashRate": 720.5,
    "bestDiffEver": "1.23M",
    "bestDiffSession": "456.7K",
    "networkDiff": "88.55T",
    "poolDiff": "65536",
    "lastDiff": "131072",
    "blkhits": 0,
    "freeHeap": 187320,
    "minFreeHeap": 163840,
    "sAccepted": 1024,
    "sRejected": 3,
    "uptimeSeconds": 86400,
    "uptimeEver": 2592000
  },
  "identity": {
    "fwVersion": "v2.9.31",
    "hwModel": "NMAxe",
    "displayName": "NMAxe",
    "hostName": "nmaxe-001",
    "ssid": "MyHomeWifi",
    "rssi": -55,
    "appSha256": "ef970b389312276b"
  },
  "fans": [
    { "id": 0, "speed": 60, "rpm": 2800 }
  ],
  "stratum": {
    "url": "stratum+tcp://pool.example.com:3333",
    "user": "bc1q...xyz.worker1",
    "pwd": "x"
  }
}