Add 47 new tests covering parse_ethtool_driver, parse_nic_stats, parse_ethtool_dom (SFP DOM), parse_ip_link, parse_dmesg, parse_lldpctl, and the analyze() health-analysis method with all issue/warning/info code paths (NO_CARRIER, HALF_DUPLEX, SPEED_MISMATCH, SFP thresholds, CRC errors, carrier flapping, LLDP mismatch/missing). Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>