Add browser inference sample manifest

sample_manifest.json

@@ -0,0 +1,13 @@
+{
+  "demo_id": "demo_20260404_082438",
+  "scenario_id": "critical_infra",
+  "dataset_id": "glu-sec04-core",
+  "dataset_title": null,
+  "rows": [],
+  "feature_keys": [],
+  "target_key": "anomaly_flag",
+  "summary": {
+    "row_count": 0,
+    "source": "none"
+  }
+}