refactor: enhance type hinting and casting for improved type safety across multiple files

app/repositories/task_repo.py

@@ -5,7 +5,7 @@ from __future__ import annotations
 from collections.abc import Mapping, Sequence
 from dataclasses import dataclass
 from datetime import datetime
-from typing import Any
+from typing import Any, cast
 
 from sqlalchemy import Select, select
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -123,6 +123,9 @@ class TaskRepository:
 
     async def _resolve_task_owner(self, task: Task) -> int | None:
         if task.deal is not None:
-            return task.deal.owner_id
+            return int(task.deal.owner_id)
         stmt = select(Deal.owner_id).where(Deal.id == task.deal_id)
-        return await self._session.scalar(stmt)
+        owner_id_raw: Any = await self._session.scalar(stmt)
+        if owner_id_raw is None:
+            return None
+        return cast(int, owner_id_raw)