fix(drivers): InitializeAsync releases previous device/session state before overwrite (#630)

FOCAS, AbLegacy, AbCip, TwinCAT, S7 and OpcUaClient orphaned the previous
probe/recycle/fixed-tree loops and clients when re-initialised on a live driver.

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7/S7Driver.cs

@@ -223,6 +223,11 @@ public sealed class S7Driver
     /// <inheritdoc />
     public async Task InitializeAsync(string driverConfigJson, CancellationToken cancellationToken)
     {
+        // #630: InitializeAsync is reachable on a live driver (DriverInstanceActor.AdoptConfigDuringInit
+        // runs it with no teardown first). Stop the previous probe loop and drop the previous connection
+        // before they are overwritten below. Deliberately NOT ShutdownAsync: that also drops _poll and the
+        // subscriptions, which nothing would re-drive.
+        await ReleaseConnectionAsync().ConfigureAwait(false);
         Health = new DriverHealth(DriverState.Initializing, null, null);
         try
         {
@@ -360,7 +365,18 @@ public sealed class S7Driver
         // disposing its CTS (drain-before-dispose, STAB-6-S7), so no poll iteration touches _gate
         // after this returns.
         await _poll.DisposeAsync().ConfigureAwait(false);
+        await ReleaseConnectionAsync().ConfigureAwait(false);
+        _writeFault = null;
+        _connectBackoff.RecordSuccess();
+        Health = new DriverHealth(DriverState.Unknown, Health.LastSuccessfulRead, null);
+    }
 
+    /// <summary>
+    ///     Cancels + bounded-joins the probe loop, then disposes its CTS and the PLC connection. The
+    ///     connection part of <see cref="ShutdownAsync"/> (everything but the poll engine and health).
+    /// </summary>
+    private async Task ReleaseConnectionAsync()
+    {
         var probeCts = _probeCts;
         var probeTask = _probeTask;
         try { probeCts?.Cancel(); } catch { }
@@ -381,11 +397,8 @@ public sealed class S7Driver
 
         _initialized = false;
         _plcDead = false;
-        _writeFault = null;
-        _connectBackoff.RecordSuccess();
         try { Plc?.Dispose(); } catch { /* best-effort — tearing down anyway */ }
         Plc = null;
-        Health = new DriverHealth(DriverState.Unknown, Health.LastSuccessfulRead, null);
     }
 
     /// <inheritdoc />