feat: Enhance timestamp management in BaseModel and PlaylistRepository; add automatic updates and improve code readability

app/models/base.py

@@ -1,6 +1,9 @@
 from datetime import UTC, datetime
+from typing import Any
 
 from sqlalchemy import event
+from sqlalchemy.engine import Connection
+from sqlalchemy.orm import Mapper
 from sqlmodel import Field, SQLModel
 
 
@@ -16,6 +19,8 @@ class BaseModel(SQLModel):
 
 # SQLAlchemy event listener to automatically update updated_at timestamp
 @event.listens_for(BaseModel, "before_update", propagate=True)
-def update_timestamp(mapper, connection, target):
+def update_timestamp(
+    mapper: Mapper[Any], connection: Connection, target: BaseModel,  # noqa: ARG001
+) -> None:
     """Automatically set updated_at timestamp before update operations."""
     target.updated_at = datetime.now(UTC)