feat: establish NekoNest Cloud control and relay

relay/internal/auditsink/audit.go

@@ -0,0 +1,24 @@
+package auditsink
+
+import (
+	"context"
+	"log/slog"
+
+	"github.com/klarkxy/nekonest/relaycore"
+)
+
+// Sink deliberately logs only event classification and error state. It never
+// serializes prompt, transcript, path, attachment, or approval payloads.
+type Sink struct{ Logger *slog.Logger }
+
+func (sink Sink) Emit(_ context.Context, event relaycore.AuditEvent) {
+	logger := sink.Logger
+	if logger == nil {
+		logger = slog.Default()
+	}
+	arguments := []any{"component", event.Component, "event", event.Name}
+	if event.Err != nil {
+		arguments = append(arguments, "error", event.Err.Error())
+	}
+	logger.Info("relay data-plane event", arguments...)
+}