feat(auditlog): AuditLogIngestActor + gRPC handler (#23)

src/ScadaLink.Commons/Messages/Audit/IngestAuditEventsCommand.cs

@@ -0,0 +1,20 @@
+using ScadaLink.Commons.Entities.Audit;
+
+namespace ScadaLink.Commons.Messages.Audit;
+
+/// <summary>
+/// Akka message sent to the central <c>AuditLogIngestActor</c> (Audit Log #23,
+/// M2 site-sync pipeline) carrying a batch of <see cref="AuditEvent"/> rows
+/// decoded by the <c>SiteStreamGrpcServer</c> from a site's
+/// <c>IngestAuditEvents</c> gRPC RPC. The actor stamps
+/// <see cref="AuditEvent.IngestedAtUtc"/> and writes the rows idempotently to
+/// the central <c>AuditLog</c> table.
+/// </summary>
+/// <remarks>
+/// Lives in <c>ScadaLink.Commons</c> rather than <c>ScadaLink.AuditLog</c>
+/// because the gRPC server in <c>ScadaLink.Communication</c> needs to construct
+/// it, and <c>ScadaLink.AuditLog</c> already references
+/// <c>ScadaLink.Communication</c> (the proto DTOs live there). Putting the
+/// message in Commons avoids a project-reference cycle.
+/// </remarks>
+public sealed record IngestAuditEventsCommand(IReadOnlyList<AuditEvent> Events);

src/ScadaLink.Commons/Messages/Audit/IngestAuditEventsReply.cs

@@ -0,0 +1,11 @@
+namespace ScadaLink.Commons.Messages.Audit;
+
+/// <summary>
+/// Reply from the central <c>AuditLogIngestActor</c> for an
+/// <see cref="IngestAuditEventsCommand"/>. <see cref="AcceptedEventIds"/> lists
+/// every row the actor considers durably persisted at central — including ids
+/// that were already present before the call (first-write-wins idempotency).
+/// The gRPC handler echoes these ids back over the wire as the <c>IngestAck</c>
+/// the site uses to flip rows to <c>Forwarded</c>.
+/// </summary>
+public sealed record IngestAuditEventsReply(IReadOnlyList<Guid> AcceptedEventIds);