WIP checkpoint: US-1: Asset Import Pipeline — glTF upload endpoint with metadata extraction

backend/app/models/asset.py

@@ -6,6 +6,8 @@ import enum
 import json
 from typing import Optional, List
 
+from pydantic import BaseModel as PydanticBaseModel
+
 from app.database import Base
 
 
@@ -42,7 +44,7 @@ class Asset(Base):
     world = relationship("World", back_populates="assets")
 
 
-class GLTFMetadata(BaseModel):
+class GLTFMetadata(PydanticBaseModel):
     """Pydantic schema for glTF asset metadata."""
     mesh_count: Optional[int] = None
     vertex_count: Optional[int] = None