1.2.0

1.2.0\n\n### Added\n- External temperature and humidity sensor support via APC SNMP Universal I/O probe OIDs.\n- Manual per-device diagnostics button with on-demand SNMP + Modbus dump output in Home Assistant.\n\n### Changed\n- Improved external probe compatibility across APC/NMC OID instance indexing variants and value scaling formats.\n- Optional external probe entities are only created when probe values are present.