feat(profiler): track SMTP victim domains per attacker

New SmtpTarget table records each (attacker, domain) pair observed via
the SMTP honeypots. Only the domain is stored — local-parts are dropped
at ingestion, so this table holds no user-identifying data beyond the
target organisation's identity.

The profiler worker extracts domains from rcpt_to / rcpt_denied /
message_accepted events, normalizes them (lowercase, strip local-part,
drop blocked TLDs), and upserts one row per pair with a running count +
first_seen / last_seen.

Three repo methods shipped:
  * increment_smtp_target(attacker, domain) — upsert + bump
  * list_smtp_targets(attacker) — per-attacker view
  * smtp_target_seen(domain) — cross-attacker aggregate, shaped as the
    federation-gossip RPC that V2 will expose.

The gossip-query shape is load-bearing: each operator can answer
"have any of your attackers targeted corp1.com?" without leaking
which attackers or when — the aggregate returns a bool + total count
+ first/last seen, nothing else.

tests/test_base_repo.py

@@ -31,6 +31,9 @@ class DummyRepo(BaseRepository):
     async def get_behaviors_for_ips(self, ips): await super().get_behaviors_for_ips(ips)
     async def upsert_session_profile(self, sid, data): await super().upsert_session_profile(sid, data)
     async def get_session_profile(self, sid): await super().get_session_profile(sid)
+    async def increment_smtp_target(self, u, d): await super().increment_smtp_target(u, d)
+    async def list_smtp_targets(self, u): await super().list_smtp_targets(u)
+    async def smtp_target_seen(self, d): await super().smtp_target_seen(d)
     async def get_attacker_by_uuid(self, u): await super().get_attacker_by_uuid(u)
     async def get_attackers(self, **kw): await super().get_attackers(**kw)
     async def get_total_attackers(self, **kw): await super().get_total_attackers(**kw)
@@ -72,6 +75,9 @@ async def test_base_repo_coverage():
     await dr.get_behaviors_for_ips({"1.1.1.1"})
     await dr.upsert_session_profile("sid", {})
     await dr.get_session_profile("sid")
+    await dr.increment_smtp_target("uuid", "corp.com")
+    await dr.list_smtp_targets("uuid")
+    await dr.smtp_target_seen("corp.com")
     await dr.get_attacker_by_uuid("a")
     await dr.get_attackers()
     await dr.get_total_attackers()