Add checkpoint manifest for EfficientNet-B3

checkpoint_manifest.json

@@ -0,0 +1,15 @@
+{
+  "current_candidate": {
+    "file": "efficientnet_b3_stanford300_best.pt",
+    "architecture": "efficientnet_b3",
+    "image_size": 300,
+    "dataset": "Stanford Cars",
+    "num_classes": 196,
+    "sha256": "9a58a217831a083c34bbe849b0880a262dfe996476ca5dddc4b218fa25bd56ac",
+    "status": "candidate_final_for_api_smoke_test"
+  },
+  "previous_baseline": {
+    "file": "best.pt",
+    "note": "Do not assume this is the current final model until promotion is done."
+  }
+}