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.AuditLog/Site/Telemetry/ISiteStreamAuditClient.cs

@@ -20,6 +20,8 @@ public interface ISiteStreamAuditClient
     /// <see cref="ScadaLink.Commons.Types.Enums.AuditForwardState.Forwarded"/>
     /// in the site SQLite queue.
     /// </summary>
+    /// <param name="batch">The batch of audit events to forward.</param>
+    /// <param name="ct">Cancellation token for the operation.</param>
     Task<IngestAck> IngestAuditEventsAsync(AuditEventBatch batch, CancellationToken ct);
 
     /// <summary>
@@ -38,5 +40,7 @@ public interface ISiteStreamAuditClient
     /// DI default (used by central and test composition roots) returns an empty
     /// ack so no rows are flipped.
     /// </remarks>
+    /// <param name="batch">The batch of cached-call telemetry packets to forward.</param>
+    /// <param name="ct">Cancellation token for the operation.</param>
     Task<IngestAck> IngestCachedTelemetryAsync(CachedTelemetryBatch batch, CancellationToken ct);
 }