fix(gateway): detect script-style gateway processes for --replace

Recognize hermes_cli/main.py gateway command lines in gateway
process detection and PID validation so --replace reliably finds
existing gateway instances.

Adds a regression test covering script-style cmdline detection.

Closes #1830

hermes_cli/gateway.py

@@ -31,6 +31,7 @@ def find_gateway_pids() -> list:
     pids = []
     patterns = [
         "hermes_cli.main gateway",
+        "hermes_cli/main.py gateway",
         "hermes gateway",
         "gateway/run.py",
     ]