feat: add wireless sensor discovery and fix YAML sensor parsing
- Add wireless sensor discovery for ePMP and AirOS devices
- Implement vendor-specific OIDs matching LibreNMS PHP discovery
- Fix table/state sensor discovery to handle map format from Client.walk
- Add discovered_sensors to debug data with values and state descriptions
- ePMP: frequency, clients, rssi, snr (rssi/snr for SM only)
- AirOS: frequency, capacity, ccq, clients, distance, noise-floor, power, quality, rate, rssi, utilization