fix(gateway): stabilize process identities

tests/gateway/test_runtime.py

@@ -642,6 +642,24 @@ def test_lease_snapshot_prunes_a_reused_client_pid(tmp_path, monkeypatch):
     }
 
 
+def test_lease_snapshot_keeps_a_legacy_localized_darwin_client(tmp_path, monkeypatch):
+    runtime = GatewayRuntime(paths=_paths(tmp_path), platform_name="Darwin")
+    started_at = int(time.mktime((2026, 8, 18, 2, 17, 54, -1, -1, -1)))
+    identity = "42:二  8/18 02:17:54 2026"
+    monkeypatch.setattr(runtime, "_is_pid_running", lambda _pid: True)
+    monkeypatch.setattr(runtime, "_process_identity", lambda _pid: identity)
+    client = GatewayClientLease(runtime, kind="webui", pid=12345, token="client")
+
+    client.acquire()
+    client.mark_ephemeral()
+    identity = f"darwin:42:{started_at}:123456"
+
+    snapshot = client.snapshot()
+
+    assert snapshot.auto_stop is True
+    assert snapshot.clients == 1
+
+
 def test_lease_snapshot_keeps_a_client_when_identity_probe_is_unavailable(
     tmp_path,
     monkeypatch,
@@ -791,6 +809,26 @@ def test_windows_host_identity_stays_safe_when_target_platform_is_posix(tmp_path
     assert runtime.process_identity(12345) == "created-at"
 
 
+def test_windows_lease_prunes_a_reused_pid_by_creation_time(tmp_path, monkeypatch):
+    runtime = GatewayRuntime(paths=_paths(tmp_path), platform_name="Windows")
+    identity = "filetime:first-process"
+    monkeypatch.setattr("nanobot.process_runtime._platform_name", lambda: "Windows")
+    monkeypatch.setattr(
+        "nanobot.process_runtime._windows_process_identity",
+        lambda _pid: identity,
+    )
+    client = GatewayClientLease(runtime, kind="tui", pid=12345, token="client")
+
+    client.acquire()
+    client.mark_ephemeral()
+    identity = "filetime:replacement-process"
+
+    snapshot = client.snapshot()
+
+    assert snapshot.auto_stop is True
+    assert snapshot.clients == 0
+
+
 def test_status_clears_stale_state(tmp_path, monkeypatch):
     runtime = GatewayRuntime(paths=_paths(tmp_path), platform_name="Linux")
     runtime.paths.run_dir.mkdir(parents=True)
@@ -877,6 +915,38 @@ def test_posix_process_identity_includes_start_time_and_accepts_legacy_state(
     assert runtime._record_matches_process({"identity": 42}, 12345) is True
 
 
+def test_darwin_process_identity_is_locale_independent(tmp_path, monkeypatch):
+    runtime = GatewayRuntime(
+        paths=_paths(tmp_path),
+        platform_name="Darwin",
+        subprocess_run=lambda *_args, **_kwargs: pytest.fail(
+            "Darwin identities must not depend on localized subprocess output"
+        ),
+    )
+    monkeypatch.setenv("LANG", "zh_CN.UTF-8")
+    monkeypatch.setenv("LC_ALL", "zh_CN.UTF-8")
+    started_at = int(time.mktime((2026, 8, 18, 2, 17, 54, -1, -1, -1)))
+    monkeypatch.setattr(
+        "nanobot.process_runtime._darwin_process_birth",
+        lambda _pid: (42, started_at, 123456),
+    )
+
+    assert runtime.process_identity(12345) == f"darwin:42:{started_at}:123456"
+    assert runtime._record_matches_process({"identity": 42}, 12345) is True
+
+
+@pytest.mark.skipif(sys.platform != "darwin", reason="requires macOS proc_pidinfo")
+def test_darwin_live_process_identity_is_stable(tmp_path):
+    runtime = GatewayRuntime(paths=_paths(tmp_path), platform_name="Darwin")
+
+    first = runtime.process_identity(os.getpid())
+    second = runtime.process_identity(os.getpid())
+
+    assert isinstance(first, str)
+    assert first.startswith("darwin:")
+    assert second == first
+
+
 def test_stop_terminates_recorded_process(tmp_path, monkeypatch):
     runtime = GatewayRuntime(paths=_paths(tmp_path), platform_name="Linux")
     runtime.paths.run_dir.mkdir(parents=True)