Expand XML docs across bridge and test code

src/ZB.MOM.WW.LmxOpcUa.Host/Domain/IGalaxyRepository.cs

@@ -10,11 +10,37 @@ namespace ZB.MOM.WW.LmxOpcUa.Host.Domain
     /// </summary>
     public interface IGalaxyRepository
     {
+        /// <summary>
+        /// Retrieves the Galaxy object hierarchy used to construct the OPC UA browse tree.
+        /// </summary>
+        /// <param name="ct">A token that cancels the repository query.</param>
+        /// <returns>A list of Galaxy objects ordered for address-space construction.</returns>
         Task<List<GalaxyObjectInfo>> GetHierarchyAsync(CancellationToken ct = default);
+
+        /// <summary>
+        /// Retrieves the Galaxy attributes that become OPC UA variables under the object hierarchy.
+        /// </summary>
+        /// <param name="ct">A token that cancels the repository query.</param>
+        /// <returns>A list of attribute definitions with MXAccess references and type metadata.</returns>
         Task<List<GalaxyAttributeInfo>> GetAttributesAsync(CancellationToken ct = default);
+
+        /// <summary>
+        /// Gets the last Galaxy deploy timestamp used to detect metadata changes that require an address-space rebuild.
+        /// </summary>
+        /// <param name="ct">A token that cancels the repository query.</param>
+        /// <returns>The latest deploy timestamp, or <see langword="null"/> when it cannot be determined.</returns>
         Task<DateTime?> GetLastDeployTimeAsync(CancellationToken ct = default);
+
+        /// <summary>
+        /// Verifies that the service can reach the Galaxy repository before it attempts to build the address space.
+        /// </summary>
+        /// <param name="ct">A token that cancels the connectivity check.</param>
+        /// <returns><see langword="true"/> when repository access succeeds; otherwise, <see langword="false"/>.</returns>
         Task<bool> TestConnectionAsync(CancellationToken ct = default);
 
+        /// <summary>
+        /// Occurs when the repository detects a Galaxy deployment change that should trigger an OPC UA rebuild.
+        /// </summary>
         event Action? OnGalaxyChanged;
     }
 }