test(update): fleet-matrix live-pid tests verify pytest as the home's gateway

collect_fleet_versions now classifies a live pid from the state file only when the
home's identity resolver verifies it (#110420); these two tests write the record about
the pytest process itself, so they verify it explicitly. Dead-pid rows are unchanged.

tests/hermes_cli/test_fleet_matrix_down_state.py

@@ -31,6 +31,13 @@ def _setup(monkeypatch, tmp_path, record: dict):
     return home
 
 
+def _verify_self_as_gateway(monkeypatch):
+    """Without a socket answer the state file is only a claim; the fallback classifies a LIVE
+    pid from it only when the home's identity resolver verifies that pid as the gateway
+    (#110420). The live-pid tests write the record about pytest itself, so verify it."""
+    monkeypatch.setattr("gateway.status.live_gateway_pid_for_home", lambda h: os.getpid())
+
+
 _DEAD_PID = 999999899  # never a live pid
 
 
@@ -100,6 +107,7 @@ def test_matching_start_time_is_still_live(monkeypatch, tmp_path):
     from gateway.status import _get_process_start_time
 
     pid = os.getpid()
+    _verify_self_as_gateway(monkeypatch)
     _setup(
         monkeypatch,
         tmp_path,
@@ -118,6 +126,7 @@ def test_matching_start_time_is_still_live(monkeypatch, tmp_path):
 
 def test_live_gateway_rows_unchanged(monkeypatch, tmp_path):
     """The live-pid path is untouched by the down-state addition."""
+    _verify_self_as_gateway(monkeypatch)
     _setup(
         monkeypatch,
         tmp_path,