docs: add XML doc comments across src + Sister Projects section in CLAUDE.md

Bulk CommentChecker pass: fills in <param>/<inheritdoc> tags on public
APIs across all 23 src/ projects so the doc-coverage gate is green. Also
adds a Sister Projects section to CLAUDE.md pointing at the MxAccess
Gateway and OtOpcUa sibling repos, and gitignores local credential
captures (*login*.txt) and the wonder-app-vd03 deploy/ artifacts.

src/ScadaLink.CLI/Commands/CommandHelpers.cs

@@ -7,6 +7,16 @@ namespace ScadaLink.CLI.Commands;
 
 internal static class CommandHelpers
 {
+    /// <summary>
+    /// Resolves the management URL, credentials, and output format, then sends <paramref name="command"/>
+    /// to the management API and returns the process exit code.
+    /// </summary>
+    /// <param name="result">Parsed command-line result from which option values are read.</param>
+    /// <param name="urlOption">Option that supplies the management URL override.</param>
+    /// <param name="formatOption">Option that supplies the output format override.</param>
+    /// <param name="usernameOption">Option that supplies the username override.</param>
+    /// <param name="passwordOption">Option that supplies the password override.</param>
+    /// <param name="command">The management command object to send.</param>
     internal static async Task<int> ExecuteCommandAsync(
         ParseResult result,
         Option<string> urlOption,
@@ -69,6 +79,9 @@ internal static class CommandHelpers
     /// is used, otherwise <c>json</c>. The <c>--format</c> option must not declare a
     /// <c>DefaultValueFactory</c> — that would mask whether the flag was supplied.
     /// </summary>
+    /// <param name="result">Parsed command-line result.</param>
+    /// <param name="formatOption">The <c>--format</c> option definition.</param>
+    /// <param name="config">Loaded CLI configuration providing the default format fallback.</param>
     internal static string ResolveFormat(ParseResult result, Option<string> formatOption, CliConfig config)
     {
         // GetResult returns non-null only when the option was actually present on the
@@ -87,6 +100,8 @@ internal static class CommandHelpers
     /// Resolves a single credential: an explicit command-line value wins, otherwise the
     /// environment-variable fallback (from <see cref="CliConfig"/>) is used.
     /// </summary>
+    /// <param name="commandLineValue">Value supplied on the command line, or null if absent.</param>
+    /// <param name="envValue">Fallback value from the config file or environment variable.</param>
     internal static string? ResolveCredential(string? commandLineValue, string? envValue)
         => string.IsNullOrWhiteSpace(commandLineValue) ? envValue : commandLineValue;
 
@@ -96,6 +111,7 @@ internal static class CommandHelpers
     /// <c>new Uri(...)</c> in the <see cref="ManagementHttpClient"/> constructor and throw
     /// an unhandled <see cref="UriFormatException"/>.
     /// </summary>
+    /// <param name="url">URL string to validate.</param>
     internal static bool IsValidManagementUrl(string? url)
     {
         if (string.IsNullOrWhiteSpace(url))
@@ -105,6 +121,11 @@ internal static class CommandHelpers
             && (uri.Scheme == Uri.UriSchemeHttp || uri.Scheme == Uri.UriSchemeHttps);
     }
 
+    /// <summary>
+    /// Writes the management response to stdout and returns the appropriate process exit code.
+    /// </summary>
+    /// <param name="response">Response received from the management API.</param>
+    /// <param name="format">Output format (<c>json</c> or <c>table</c>).</param>
     internal static int HandleResponse(ManagementResponse response, string format)
     {
         if (response.JsonData != null)