New TTL-cached threat-intel row keyed by attacker IP, with per-provider
verdict/raw/queried_at columns for GreyNoise, AbuseIPDB, abuse.ch Feodo
Tracker and ThreatFox. Carries schema_version from day one (federation
wire-format precedent set by SessionProfile). Repo gains
upsert_attacker_intel, get_attacker_intel_by_ip, and a
get_unenriched_attacker_ips backfill primitive that picks fresh + stale
rows for the forthcoming 'decnet enrich' worker.
Also documents the open-source intel-source backlog in DEVELOPMENT_V2.
