Changes
- Replace isc-dhcp-server (dhcpd) with kea-dhcp4 as the DHCP backend for the Captive Portal attack: JSON config generation, lease file relocated to /var/lib/kea/kea-leases4.csv, client IP/MAC/hostname lookup reworked against kea's CSV lease format, AppArmor local override handling updated for the kea-dhcp4 profile, dependency check/cleanup/diagnostics updated accordingly. Closes #1248.