fix(gateway): generalize supervised-gateway exemption in orphan reaper to all platforms

Compose the service-PID exclusion (#85743, RelaxJonh) and the recorded-PID +
parent-chain exemption (#86100, arccat-114) into one cross-platform rule:

- _get_service_pids() exclusion now runs unconditionally, not only under
  is_macos() — it is the authoritative "supervised" signal for launchd and
  any systemd unit visible on a host that got past the systemd gate.
- The recorded-healthy-gateway (get_running_pid()) + parent-chain exemption
  now runs on every platform, not only Windows. A recorded, liveness-verified
  gateway is by definition not an orphan "the pidfile/runtime record can't
  see", so the reaper must never target it — this covers Windows Scheduled
  Task / Startup VBS supervision, standalone launcher-started gateways
  (the case #85743 alone would miss), and macOS/WSL equivalents.

True orphans (no service registration, no valid runtime record) are still
found and reaped, preserving the #51325/#75936 duplicate-port protection.

Existing macOS regression tests updated to pin get_running_pid to None for
their scenario; Windows regression tests from #86100 carry over unchanged.

Bug class: #83683 (root), #86287, #86098, #85738, #85368, #85344, #85044,
#84855, #84824, #84200.

hermes_cli/gateway.py

@@ -1555,44 +1555,42 @@ def _reap_unsupervised_gateway_orphans(extra_exclude: set | None = None) -> bool
     own = {os.getpid()}
     if extra_exclude:
         own |= extra_exclude
-    # On macOS, exclude the launchd-managed gateway PID so the orphan reaper
-    # doesn't kill a supervised gateway when Hermes Desktop opens (the serve
-    # process calls this on startup).  supports_systemd_services() returns
-    # False on macOS, so without this the launchd gateway looks like an
-    # unsupervised orphan and gets SIGTERM'd, causing launchd to restart it.
-    if is_macos():
-        try:
-            own |= _get_service_pids()
-        except Exception:
-            pass
-    # On Windows there is no systemd/launchd service query to fall back on
+    # Service-managed gateways are not orphans — never reap them.  This
+    # covers macOS launchd (supports_systemd_services() is False there, so
+    # without this the launchd gateway looks like an unsupervised orphan and
+    # gets SIGTERM'd, causing launchd to restart it — or leaving it down
+    # under KeepAlive.SuccessfulExit=false) and any systemd unit reachable
+    # from a host that got past the gate above (#83683, #85344).
+    try:
+        own |= _get_service_pids()
+    except Exception:
+        pass
+    # On Windows there is no systemd/launchd service query at all
     # (_get_service_pids() returns an empty set), so a gateway supervised by
     # a Scheduled Task / Startup VBS looks like an unsupervised orphan to the
-    # process scan.  Exempt the recorded healthy gateway PID and its parent
-    # chain: the Scheduled Task launches a ``gateway run`` bootstrap whose
-    # argv matches the gateway scan, and killing that bootstrap takes the
-    # detached gateway it spawned down with it (#86098).
-    if is_windows():
-        try:
-            from gateway.status import get_running_pid
-
-            recorded = get_running_pid()
-            if recorded and recorded > 0:
-                own.add(recorded)
-                try:
-                    import psutil  # type: ignore
-
-                    parent = psutil.Process(recorded).parent()
-                    while parent is not None:
-                        own.add(parent.pid)
-                        parent = parent.parent()
-                except Exception:
-                    pass
-        except Exception:
-            pass
+    # process scan (#86098).  The same holds on every platform for a healthy
+    # gateway launched standalone (no service registration) whose PID the
+    # runtime record can see (#83683).  Exempt the recorded healthy gateway
+    # PID and its parent chain: a recorded, liveness-verified gateway is by
+    # definition not an orphan "the pidfile/runtime record can't see", and
+    # the Scheduled-Task bootstrap's argv (``gateway run``) matches the
+    # gateway scan — killing that bootstrap takes the detached gateway it
+    # spawned down with it.
     try:
-        # launchd/systemd-supervised gateways are not orphans — never reap them.
-        own |= _get_service_pids()
+        from gateway.status import get_running_pid
+
+        recorded = get_running_pid()
+        if recorded and recorded > 0:
+            own.add(recorded)
+            try:
+                import psutil  # type: ignore
+
+                parent = psutil.Process(recorded).parent()
+                while parent is not None:
+                    own.add(parent.pid)
+                    parent = parent.parent()
+            except Exception:
+                pass
     except Exception:
         pass
     try:

tests/hermes_cli/test_gateway.py

@@ -447,6 +447,8 @@ class TestReapUnsupervisedGatewayOrphansMacOS:
 
         # _get_service_pids returns the launchd-managed gateway PID.
         monkeypatch.setattr(gateway, "_get_service_pids", lambda: {launchd_pid})
+        # No pidfile-recorded gateway in this scenario.
+        monkeypatch.setattr("gateway.status.get_running_pid", lambda: None)
 
         # find_gateway_pids returns the launchd PID plus a real orphan.
         # The reaper should only kill the orphan, not the launchd PID.
@@ -478,6 +480,7 @@ class TestReapUnsupervisedGatewayOrphansMacOS:
         monkeypatch.setattr(gateway, "is_macos", lambda: True)
         monkeypatch.setattr(gateway, "supports_systemd_services", lambda: False)
         monkeypatch.setattr(gateway, "_get_service_pids", lambda: {launchd_pid})
+        monkeypatch.setattr("gateway.status.get_running_pid", lambda: None)
 
         # find_gateway_pids would return the launchd PID, but it's excluded.
         monkeypatch.setattr(