fix(agent99): serialize cross-process SSH transport

apps/api/tests/test_agent99_transport_recovery_deploy_contract.py

@@ -118,3 +118,21 @@ def test_agent99_bounds_stale_ssh_processes_without_touching_tunnels() -> None:
         "staleMinutes": 15,
         "hardStaleMinutes": 60,
     }
+
+
+def test_agent99_serializes_ssh_across_scheduled_task_processes() -> None:
+    source = CONTROL.read_text(encoding="utf-8")
+    config = json.loads((ROOT / "agent99.config.99.example.json").read_text())
+
+    assert "function Enter-AgentSshTransportLock" in source
+    assert "[IO.FileShare]::None" in source
+    assert '"ssh-transport.lock"' in source
+    invoke_ssh = source[source.index("function Invoke-SshText") :]
+    assert "Enter-AgentSshTransportLock" in invoke_ssh
+    assert "Exit-AgentSshTransportLock" in invoke_ssh
+    assert "ssh_transport_lock_failed" in source
+    assert config["sshTransport"] == {
+        "serialized": True,
+        "lockTimeoutSeconds": 90,
+        "lockPollMilliseconds": 200,
+    }