fix(runtime): verify namespace init death and record Wave 3-S validation

tests/containment_helpers.py

@@ -1,5 +1,7 @@
 """Captured spawns exercise the production runner without signalling fake PIDs."""
 import asyncio
+import json
+import os
 from types import SimpleNamespace
 
 from src import containment
@@ -13,6 +15,9 @@ def capture_owned_spawn(monkeypatch, tmp_path):
 
     async def fake_exec(*argv, **kwargs):
         captured.update(argv=argv, kwargs=kwargs, command=argv[-1])
+        if "--info-fd" in argv:
+            fd = int(argv[argv.index("--info-fd") + 1])
+            os.write(fd, json.dumps({"child-pid": 99999998}).encode())
         stdout = asyncio.StreamReader()
         if "ody-boundary" in argv:
             stdout.feed_data((argv[argv.index("ody-boundary") + 1] + "\n").encode())
@@ -33,6 +38,9 @@ def capture_owned_spawn(monkeypatch, tmp_path):
         return containment.ReleaseOutcome(dead=True, escalated=False)
 
     monkeypatch.setattr(asyncio, "create_subprocess_exec", fake_exec)
+    real_capture = containment.process_ownership.capture
+    monkeypatch.setattr(containment.process_ownership, "capture", lambda pid:
+        {"pid": pid, "start_token": "captured-fake"} if pid in (99999998, 99999999) else real_capture(pid))
     if hasattr(containment.os, "pidfd_open"):
         monkeypatch.delattr(containment.os, "pidfd_open")
     monkeypatch.setattr(containment, "_release_awaited", release)