Allow /stop without target argument

tests/test_bridge.py

@@ -132,6 +132,21 @@ def test_unknown_target_is_rejected(monkeypatch) -> None:
     )
 
 
+def test_stop_command_ignores_empty_target(monkeypatch) -> None:
+    FakePtyManager.instances.clear()
+    bridge = _make_bridge(monkeypatch)
+    bridge._handle_command("start", "codex", "C1")
+
+    bridge._handle_command("stop", "", "C1")
+
+    assert bridge.pty is None
+    assert bridge._active_target is None
+    assert bridge.slack.sent_messages[-1] == (
+        "C1",
+        ":electric_plug: 세션 연결이 해제되었습니다.",
+    )
+
+
 def test_handle_message_resets_last_sent_output_after_input(monkeypatch) -> None:
     FakePtyManager.instances.clear()
     bridge = _make_bridge(monkeypatch)