deprecate(lmxproxy): move all LmxProxy code, tests, and docs to deprecated/

LmxProxy is no longer needed. Moved the entire lmxproxy/ workspace, DCL
adapter files, and related docs to deprecated/. Removed LmxProxy registration
from DataConnectionFactory, project reference from DCL, protocol option from
UI, and cleaned up all requirement docs.

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

@@ -0,0 +1,30 @@
+using System.Collections.Generic;
+
+namespace ZB.MOM.WW.LmxProxy.Host.Domain
+{
+    /// <summary>
+    ///     Subscription statistics for all clients and tags.
+    /// </summary>
+    public class SubscriptionStats
+    {
+        /// <summary>
+        ///     Gets or sets the total number of clients.
+        /// </summary>
+        public int TotalClients { get; set; }
+
+        /// <summary>
+        ///     Gets or sets the total number of tags.
+        /// </summary>
+        public int TotalTags { get; set; }
+
+        /// <summary>
+        ///     Gets or sets the mapping of tag addresses to client counts.
+        /// </summary>
+        public Dictionary<string, int> TagClientCounts { get; set; } = new();
+
+        /// <summary>
+        ///     Gets or sets the mapping of client IDs to their statistics.
+        /// </summary>
+        public Dictionary<string, ClientStats> ClientStats { get; set; } = new();
+    }
+}