feat(geoip): country-code enrichment via RIR delegated-stats

Populates Attacker.country_code + country_source (MVP) using the five
RIR delegated-stats files (ARIN/RIPE/APNIC/LACNIC/AFRINIC). Offline,
license-free, no outbound traffic that could burn honeypot stealth.

- decnet.geoip package with factory/base/lookup + rir/ subpackage
  (fetch/parse/provider) mirroring the db + bus factory convention
- Profiler._build_record calls enrich_ip on every upsert
- Idempotent ALTER TABLE migrations for both SQLite and MySQL
- decnet geoip refresh/lookup CLI (master-only)
- /var/lib/decnet/geoip seeded by decnet init
- DECNET_GEOIP_ENABLED=false kill-switch; set in tests/conftest.py so
  unit tests never trigger the first-access fetch

decnet/cli/gating.py

@@ -31,7 +31,7 @@ MASTER_ONLY_COMMANDS: frozenset[str] = frozenset({
     "services", "distros", "correlate", "archetypes", "web",
     "db-reset", "init",
 })
-MASTER_ONLY_GROUPS: frozenset[str] = frozenset({"swarm", "topology"})
+MASTER_ONLY_GROUPS: frozenset[str] = frozenset({"swarm", "topology", "geoip"})
 
 
 def _agent_mode_active() -> bool: