Add model size metadata (as loaded, still need to convert vision backbone to fp32)

model.safetensors.index.json

@@ -1,6 +1,6 @@
 {
     "metadata": {
-        "total_size": 0
+        "total_size": 41297598464
     },
     "weight_map": {
         "model.transformer.wte.embedding": "model-00001-of-00010.safetensors",
@@ -2553,4 +2553,4 @@
         "model.vision_backbone.image_projector.w2.weight": "model-00010-of-00010.safetensors",
         "model.vision_backbone.image_projector.w3.weight": "model-00010-of-00010.safetensors"
     }
-}
+}