The parser only recognized address=/ and server=/ prefixes but not
local=/, which is the format used by Hagezi blocklists. This caused
~270k domains to be stored with the raw "local=/domain/" string as
the domain name, breaking allow-list matching.
Adds Pi-hole-style DNS filtering using dnsmasq's native address=/ directives,
which block domains and all subdomains. Users subscribe to blocklists by URL
or upload files, with suggested lists from Hagezi, Steven Black, and OISD.
Background runner refreshes lists on a configurable interval (default 24h).
