Add chunk_001 merge_summary.json (phase1 sentinel for phase2 worker)

fridge_m_0.7_pd/chunk_001/merge_summary.json

@@ -0,0 +1,31 @@
+{
+  "chunk": "chunk_001",
+  "shards_processed": 4,
+  "trajs_merged": 40,
+  "trajs_skipped_no_full_state": 0,
+  "trajs_mapping_missing": 0,
+  "trajs_failed_marked": 0,
+  "source_trajs_total": 40,
+  "per_source_h5": {
+    "trajectories_batch_1_of_4_cam_rand.h5": {
+      "total": 8,
+      "merged": 8,
+      "failed": 0
+    },
+    "trajectories_batch_2_of_4_cam_rand.h5": {
+      "total": 9,
+      "merged": 9,
+      "failed": 0
+    },
+    "trajectories_batch_3_of_4_cam_rand.h5": {
+      "total": 13,
+      "merged": 13,
+      "failed": 0
+    },
+    "trajectories_batch_4_of_4_cam_rand.h5": {
+      "total": 10,
+      "merged": 10,
+      "failed": 0
+    }
+  }
+}