feat(lmxproxy): phase 1 — v2 protocol types and domain model

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

lmxproxy/src-reference/ZB.MOM.WW.LmxProxy.Host/Domain/ConnectionState.cs

@@ -0,0 +1,38 @@
+namespace ZB.MOM.WW.LmxProxy.Host.Domain
+{
+    /// <summary>
+    ///     Represents the state of a SCADA client connection.
+    /// </summary>
+    public enum ConnectionState
+    {
+        /// <summary>
+        ///     The client is disconnected.
+        /// </summary>
+        Disconnected,
+
+        /// <summary>
+        ///     The client is in the process of connecting.
+        /// </summary>
+        Connecting,
+
+        /// <summary>
+        ///     The client is connected.
+        /// </summary>
+        Connected,
+
+        /// <summary>
+        ///     The client is in the process of disconnecting.
+        /// </summary>
+        Disconnecting,
+
+        /// <summary>
+        ///     The client encountered an error.
+        /// </summary>
+        Error,
+
+        /// <summary>
+        ///     The client is reconnecting after a connection loss.
+        /// </summary>
+        Reconnecting
+    }
+}