feat(lmxproxy): active health probing + address-based subscription cleanup (gap 1 & 2)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lmxproxy/src/ZB.MOM.WW.LmxProxy.Host/MxAccess/MxAccessClient.Subscription.cs

@@ -47,6 +47,15 @@ namespace ZB.MOM.WW.LmxProxy.Host.MxAccess
             return new SubscriptionHandle(this, addressList, callback);
         }
 
+        /// <summary>
+        ///     Unsubscribes specific addresses by address name.
+        ///     Removes from both COM state and stored subscriptions (no reconnect replay).
+        /// </summary>
+        public async Task UnsubscribeByAddressAsync(IEnumerable<string> addresses)
+        {
+            await UnsubscribeAsync(addresses);
+        }
+
         /// <summary>
         ///     Unsubscribes specific addresses.
         /// </summary>