feat(smtp_relay): ingest probe_forwarded as probe_relay bounty

Adds probe_forwarded to meaningful event kinds and stores it in the
bounty table as bounty_type=probe_relay with forwarded=true/false, so
the dashboard shows whether the upstream actually accepted the test email.

decnet/correlation/event_kinds.py

@@ -41,6 +41,10 @@ INTERACTION_EVENT_TYPES: frozenset[str] = frozenset({
     "rcpt_to",
     "rcpt_denied",
     "message_accepted",
+    # probe_forwarded fires when we actually relay the test email upstream
+    # so the attacker can verify receipt. forwarded=1 means the upstream
+    # accepted it; forwarded=0 means it failed (but the attacker still got 250).
+    "probe_forwarded",
     # File / payload activity
     "file_captured",
     "upload",

decnet/web/ingester.py

@@ -613,6 +613,21 @@ async def _extract_bounty(
                 "content_type": _fields.get("content_type"),
             },
         })
+    elif _evt == "probe_forwarded":
+        # Record whether the upstream relay accepted the probe. forwarded=1
+        # means the attacker's test email actually landed in their inbox;
+        # forwarded=0 means the upstream refused (attacker still got 250).
+        await repo.add_bounty({
+            "decky": log_data.get("decky"),
+            "service": log_data.get("service"),
+            "attacker_ip": log_data.get("attacker_ip"),
+            "bounty_type": "probe_relay",
+            "payload": {
+                "msg_id": _fields.get("msg_id"),
+                "forwarded": _fields.get("forwarded") == "1",
+                "delivery_count": _fields.get("delivery_count"),
+            },
+        })
 
 
 # ─── IP-leak detection (XFF / Forwarded / X-Real-IP / CDN variants) ──────────