docs: complete XML doc coverage (returns, summaries, inheritdoc)

Resolve all 622 issues flagged by the enhanced CommentChecker: add missing
<returns> tags (incl. the standard phrasing on non-generic Task methods),
add missing <summary> tags, and replace misused/redundant <inheritdoc/> on
members that override or implement nothing with real documentation.
Documentation-only — no behavior change; solution builds clean.

src/ZB.MOM.WW.ScadaBridge.CLI/Commands/NotificationCommands.cs

@@ -13,6 +13,7 @@ public static class NotificationCommands
     /// <param name="formatOption">Global <c>--format</c> option for output format.</param>
     /// <param name="usernameOption">Global <c>--username</c> option for authentication.</param>
     /// <param name="passwordOption">Global <c>--password</c> option for authentication.</param>
+    /// <returns>The configured <c>notification</c> command with all sub-commands registered.</returns>
     public static Command Build(Option<string> urlOption, Option<string> formatOption, Option<string> usernameOption, Option<string> passwordOption)
     {
         var command = new Command("notification") { Description = "Manage notification lists" };
@@ -131,6 +132,7 @@ public static class NotificationCommands
     /// null when omitted so the server-side handler preserves the existing values.
     /// </summary>
     /// <param name="result">The parsed command-line result from the <c>smtp update</c> invocation.</param>
+    /// <returns>An <see cref="UpdateSmtpConfigCommand"/> populated from the parsed result.</returns>
     internal static UpdateSmtpConfigCommand BuildUpdateSmtpConfigCommand(ParseResult result)
     {
         var id = result.GetValue(SmtpIdOption);