feat: Implement project management with new models, repositories, and API endpoints, and enhance character management with project association and DTOs.

models/Asset.py

@@ -28,6 +28,8 @@ class Asset(BaseModel):
     minio_thumbnail_object_name: Optional[str] = None
     thumbnail: Optional[bytes] = None
     tags: List[str] = []
+    created_by: Optional[str] = None
+    project_id: Optional[str] = None
     created_at: datetime = Field(default_factory=lambda: datetime.now(UTC))
     updated_at: datetime = Field(default_factory=lambda: datetime.now(UTC))