Add configurable non-transparent OPC UA server redundancy

Separates ApplicationUri from namespace identity so each instance in a
redundant pair has a unique server URI while sharing the same Galaxy
namespace. Exposes RedundancySupport, ServerUriArray, and dynamic
ServiceLevel through the standard OPC UA server object. ServiceLevel
is computed from role (Primary/Secondary) and runtime health (MXAccess
and DB connectivity). Adds CLI redundancy command, second deployed
service instance, and 31 new tests including paired-server integration.

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

src/ZB.MOM.WW.LmxOpcUa.Host/OpcUa/RedundancyModeResolver.cs

@@ -0,0 +1,41 @@
+using System;
+using Opc.Ua;
+using Serilog;
+
+namespace ZB.MOM.WW.LmxOpcUa.Host.OpcUa
+{
+    /// <summary>
+    /// Maps a configured redundancy mode string to the OPC UA <see cref="RedundancySupport"/> enum.
+    /// </summary>
+    public static class RedundancyModeResolver
+    {
+        private static readonly ILogger Log = Serilog.Log.ForContext(typeof(RedundancyModeResolver));
+
+        /// <summary>
+        /// Resolves the configured mode string to a <see cref="RedundancySupport"/> value.
+        /// Returns <see cref="RedundancySupport.None"/> when redundancy is disabled or the mode is unrecognized.
+        /// </summary>
+        /// <param name="mode">The mode string from configuration (e.g., "Warm", "Hot").</param>
+        /// <param name="enabled">Whether redundancy is enabled.</param>
+        /// <returns>The resolved redundancy support mode.</returns>
+        public static RedundancySupport Resolve(string mode, bool enabled)
+        {
+            if (!enabled)
+                return RedundancySupport.None;
+
+            var resolved = (mode ?? "").Trim().ToLowerInvariant() switch
+            {
+                "warm" => RedundancySupport.Warm,
+                "hot" => RedundancySupport.Hot,
+                _ => RedundancySupport.None
+            };
+
+            if (resolved == RedundancySupport.None)
+            {
+                Log.Warning("Unknown redundancy mode '{Mode}' — falling back to None. Supported modes: Warm, Hot", mode);
+            }
+
+            return resolved;
+        }
+    }
+}