docs(xmldoc): fill missing XML docs + strip tracking-ID comments across src

Adds <summary>/<param>/<returns>/<inheritdoc> where missing and removes
project bookkeeping IDs (task/tracking refs) from shipped code comments,
so the docs read cleanly and CommentChecker is quiet except for known
false positives (PLC/protocol terms, event/IEqualityComparer inheritdoc).
Doc/comment-only; no logic changed; solution builds clean.

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OpcUaApplicationHost.cs

@@ -122,6 +122,7 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
     /// <summary>Starts the OPC UA application and server.</summary>
     /// <param name="server">The standard server instance to start.</param>
     /// <param name="cancellationToken">A cancellation token for the operation.</param>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     public async Task StartAsync(StandardServer server, CancellationToken cancellationToken)
     {
         _server = server;
@@ -377,6 +378,7 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
     /// listening endpoints — the misconfiguration is logged and very visible.
     /// </summary>
     /// <param name="profiles">The security profiles to build policies for.</param>
+    /// <returns>The SDK security policies for the requested profiles.</returns>
     internal static IEnumerable<ServerSecurityPolicy> BuildSecurityPolicies(IEnumerable<OpcUaSecurityProfile> profiles)
     {
         var seen = new HashSet<OpcUaSecurityProfile>();
@@ -424,6 +426,7 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
     /// project supplies the LDAP adapter, and <see cref="NullOpcUaUserAuthenticator"/> denies all
     /// UserName logins when none is registered.
     /// </summary>
+    /// <returns>The Anonymous and UserName token policies.</returns>
     internal static IEnumerable<UserTokenPolicy> BuildUserTokenPolicies()
     {
         yield return new UserTokenPolicy(UserTokenType.Anonymous)
@@ -439,6 +442,7 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
     }
 
     /// <summary>Disposes the application host and cleans up resources.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     public async ValueTask DisposeAsync()
     {
         if (_impersonateHandler is not null && _server?.CurrentInstance?.SessionManager is { } sessionManager)