models + refactor

api/models/AssetDTO.py

@@ -1,5 +1,4 @@
 from datetime import datetime
-from typing import List, Optional
 
 from pydantic import BaseModel
 
@@ -11,10 +10,10 @@ class AssetResponse(BaseModel):
     name: str
     type: str # uploaded / generated
     content_type: str # image / prompt
-    linked_char_id: Optional[str] = None
+    linked_char_id: str | None = None
     created_at: datetime
-    url: Optional[str] = None
+    url: str | None = None
 
 class AssetsResponse(BaseModel):
-    assets: List[AssetResponse]
+    assets: list[AssetResponse]
     total_count: int