WIP checkpoint: Scaffold FastAPI backend project structure

backend/app/models/asset.py

@@ -0,0 +1,36 @@
+from sqlalchemy import Column, Integer, String, ForeignKey, Text, DateTime, Enum as SAEnum
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+import enum
+
+from app.database import Base
+
+
+class AssetType(str, enum.Enum):
+    IMAGE = "image"
+    AUDIO = "audio"
+    VIDEO = "video"
+    DOCUMENT = "document"
+    MODEL_3D = "model_3d"
+    OTHER = "other"
+
+
+class Asset(Base):
+    __tablename__ = "assets"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(255), nullable=False)
+    description = Column(Text, nullable=True)
+    asset_type = Column(SAEnum(AssetType), nullable=False)
+    file_path = Column(String(512), nullable=False)
+    file_size = Column(Integer, nullable=True)
+    mime_type = Column(String(128), nullable=True)
+    metadata_json = Column(Text, nullable=True)
+    world_id = Column(Integer, ForeignKey("worlds.id"), nullable=True)
+    owner_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    is_public = Column(Integer, default=0, nullable=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+
+    owner = relationship("User", back_populates="assets")
+    world = relationship("World", back_populates="assets")