fix: host_silence proactive notify when event is None

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/services/host_silence_scan.py

@@ -114,6 +114,13 @@ def dispatch_host_silence_notifications(db: Session, results: list[HostSilenceSc
     for item in results:
         if not item.created:
             continue
-        notify_problem(item.problem, event=None, db=db)
-        sent += 1
+        try:
+            notify_problem(item.problem, event=None, db=db)
+            sent += 1
+        except Exception:
+            logger.exception(
+                "host_silence notify failed host=%s problem_id=%s",
+                item.hostname,
+                item.problem.id,
+            )
     return sent

backend/app/services/telegram_templates.py

@@ -543,8 +543,6 @@ def format_problem_telegram_html(problem: Problem, event: Event | None = None) -
     msg += f"\n<b>{html_escape(problem.title)}</b>\n{html_escape(problem.summary)}"
     if event is not None:
         msg += f"\n\n<i>Триггер:</i> {html_escape(event.type)} ({html_escape(event.severity)})"
-    elif problem.rule_id == "rule:host_silence":
-        msg += "\n\n<i>Триггер:</i> периодическая проверка SAC (host_silence scan)"
         if event.type in (
             "rdp.login.success",
             "rdp.login.failed",
@@ -557,4 +555,6 @@ def format_problem_telegram_html(problem: Problem, event: Event | None = None) -
             "smb.admin_share.access",
         ):
             msg += "\n" + _format_event_body_html(event)
+    elif problem.rule_id == "rule:host_silence":
+        msg += "\n\n<i>Триггер:</i> периодическая проверка SAC (host_silence scan)"
     return append_notification_source_html(msg, generated_by="sac")

backend/tests/test_telegram_templates.py

@@ -326,3 +326,32 @@ def test_agent_inventory_hardware_change_template():
     assert "железо" in text.lower() or "Изменилось" in text
     assert "memory_gb" in text
     assert "32" in text
+
+
+def test_format_problem_host_silence_scan_without_event():
+    from app.models import Host, Problem
+    from app.services.problem_rules import RULE_HOST_SILENCE
+    from app.services.telegram_templates import format_problem_telegram_html
+
+    host = Host(
+        hostname="YURKOV-PC",
+        os_family="windows",
+        product="rdp-login-monitor",
+        last_seen_at=datetime(2026, 6, 11, 9, 0, tzinfo=timezone.utc),
+    )
+    problem = Problem(
+        host_id=1,
+        host=host,
+        title="Host silence: YURKOV-PC",
+        summary="Нет свежего agent.heartbeat более 300 мин",
+        severity="high",
+        status="open",
+        rule_id=RULE_HOST_SILENCE,
+        fingerprint="fp-silence",
+        event_count=0,
+        last_seen_at=datetime(2026, 6, 11, 9, 0, tzinfo=timezone.utc),
+    )
+    text = format_problem_telegram_html(problem, event=None)
+    assert "периодическая проверка SAC" in text
+    assert "host_silence scan" in text
+    assert "YURKOV-PC" in text or "UNMS" not in text  # host label uses hostname