Synthesize the covering CIDR at lookup time from the matched iptoasn
range using ipaddress.summarize_address_range. AsnInfo.prefix is
populated per-query; not persisted in the pickle cache.
enrich_ip now returns (asn, as_name, bgp_prefix, provider_name).
Profiler worker updated to unpack the 4-tuple and write bgp_prefix
into the attacker record dict.
