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/DebugStreamHelpers.cs

@@ -25,6 +25,8 @@ internal static class DebugStreamHelpers
     /// (Ctrl+C during connect) is a graceful shutdown — exit 0, no error printed.
     /// Anything else is a genuine connection failure — exit 1.
     /// </summary>
+    /// <param name="ex">The exception thrown by HubConnection.StartAsync.</param>
+    /// <param name="cancellationRequested">True when the user requested cancellation (Ctrl+C) before the exception was thrown.</param>
     internal static ConnectFailure ClassifyConnectFailure(Exception ex, bool cancellationRequested)
     {
         if (cancellationRequested && ex is OperationCanceledException)
@@ -40,6 +42,7 @@ internal static class DebugStreamHelpers
     /// a brief grace period covers a termination that races with cancellation. If no
     /// result is ever produced (pure Ctrl+C), the stream ended gracefully — exit 0.
     /// </summary>
+    /// <param name="exitTask">The task whose result is the intended exit code, set by OnStreamTerminated or the Closed handler.</param>
     internal static async Task<int> ResolveStreamExitCodeAsync(Task<int> exitTask)
     {
         if (exitTask.IsCompletedSuccessfully)