fix: Telegram footer shows SAC as sender when SAC delivers the message

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

backend/tests/test_telegram_templates.py

@@ -65,7 +65,7 @@ def test_rdp_success_template():
     text = format_event_telegram_html(event)
     assert "УСПЕШНЫЙ" in text
     assert "Сеть/RDP" in text
-    assert "📡 Оповещение: агент" in text
+    assert "📡 Оповещение: SAC (Security Alert Center)" in text
 
 
 def test_event_telegram_includes_sac_source_for_sac_daily_report():
@@ -107,7 +107,26 @@ def test_lifecycle_started_template():
     assert "K6A-DC3" in text
     assert "1.2.30-SAC" in text
     assert "загрузка ОС" in text
-    assert "📡 Оповещение: агент" in text
+    assert "📡 Оповещение: SAC (Security Alert Center)" in text
+
+
+def test_lifecycle_footer_uses_telegram_via_agent_when_present():
+    host = Host(hostname="WIN01", display_name="H1", os_family="windows")
+    event = Event(
+        event_id="00000000-0000-4000-8000-000000000506",
+        host_id=1,
+        host=host,
+        occurred_at=datetime(2026, 5, 29, 9, 0, tzinfo=timezone.utc),
+        category="agent",
+        type="agent.lifecycle",
+        severity="info",
+        title="started",
+        summary="x",
+        details={"lifecycle": "started", "telegram_via": "agent"},
+        payload={"source": {"product": "rdp-login-monitor", "product_version": "1.2.30-SAC"}},
+    )
+    text = format_event_telegram_html(event)
+    assert "📡 Оповещение: агент (rdp-login-monitor 1.2.30-SAC)" in text
 
 
 def test_rdp_shadow_control_template():