fix: add production build stub for mock integration

internal/monitoring/mock_stub.go

@@ -0,0 +1,10 @@
+// +build production
+
+package monitoring
+
+import "github.com/rcourtman/pulse-go-rewrite/internal/models"
+
+// getMockState returns nil in production builds
+func getMockState() *models.StateSnapshot {
+	return nil
+}