fix(notification): ensure BuildNotificationList returns an empty slice instead of nil

internal/builders/notification_builder_test.go

@@ -0,0 +1,18 @@
+package builders
+
+import (
+	"testing"
+
+	"cs-agent/internal/models"
+)
+
+func TestBuildNotificationListReturnsEmptySlice(t *testing.T) {
+	results := BuildNotificationList([]models.Notification{})
+
+	if results == nil {
+		t.Fatalf("expected empty slice, got nil")
+	}
+	if len(results) != 0 {
+		t.Fatalf("expected empty slice, got %d items", len(results))
+	}
+}