feat: Separate asset origin type from content type for improved asset categorization and handling.

api/models/AssetDTO.py

@@ -9,7 +9,8 @@ from models.Asset import Asset
 class AssetResponse(BaseModel):
     id: str
     name: str
-    type: str
+    type: str # uploaded / generated
+    content_type: str # image / prompt
     linked_char_id: Optional[str] = None
     created_at: datetime
     url: Optional[str] = None