fix(twincat): replay native ADS notifications after reconnect (archreview STAB-2 / Critical 4)

Native ADS notifications (the default subscribe mode) were stored as opaque handles
with no record of the symbol/type/interval/handler needed to replay. On a client swap
(EnsureConnectedAsync building a fresh client after a drop) the notifications were
silently orphaned — no Bad status, no error, pushes just stopped until redeploy.
Compounding: the IsConnected fast-path keys on AMS-port state, not wire liveness, and
a probe failure only transitioned state without recycling the dead client.

Fix:
- Store REPLAYABLE INTENT: NativeRegistration (symbol/type/bit/interval/onChange +
  swappable live handle) hung off DeviceState.NativeRegistrations, populated by
  SubscribeAsync via RegisterNotificationAsync (under ConnectGate).
- Split EnsureConnectedAsync into a gate wrapper + EnsureConnectedUnderGateAsync core;
  when the core installs a NEW client it replays every stored intent onto it and swaps
  the live handle (disposing the dead one). Register + replay both run under ConnectGate
  so they can't race.
- Probe loop: on a wire-probe failure (false or throw) RecycleClientAsync disposes+nulls
  the client so the next tick rebuilds + replays — closes the fast-path-keys-on-port-state
  compounding bug.

No TwinCAT docker fixture exists (integration needs a real TC3 XAR), so the fake-client
unit tests are the authoritative coverage:
- 4 new guards in TwinCATReconnectReplayTests (replay-onto-fresh-client + push reaches
  OnDataChange + old handle disposed; replay-all-tags; unsubscribe-after-reconnect stops
  replaying; probe-failure recycles+rebuilds).
- Full TwinCAT unit suite 174/174 green; full solution builds 0 errors.

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Tests/FakeTwinCATClient.cs

@@ -42,6 +42,11 @@ internal class FakeTwinCATClient : ITwinCATClient
     /// <summary>Test hook — fire the symbol-version-changed signal as the real client would.</summary>
     public void FireSymbolVersionChanged() => OnSymbolVersionChanged?.Invoke(this, EventArgs.Empty);
 
+    /// <summary>Test hook — simulate a wire-level drop that leaves the AMS port "connected" but dead:
+    ///     flips <see cref="IsConnected"/> to false without disposing, so the driver's IsConnected
+    ///     fast-path treats the client as stale and rebuilds (exercises the STAB-2 reconnect+replay).</summary>
+    public void SimulateWireDrop() => IsConnected = false;
+
     /// <summary>Simulates connecting to the TwinCAT system.</summary>
     /// <param name="address">The AMS address to connect to.</param>
     /// <param name="timeout">The connection timeout.</param>