Refactor code for improved readability and consistency

- Reformatted function signatures in `organization_service.py` and `task_service.py` for better alignment.
- Updated import statements across multiple files for consistency and organization.
- Enhanced test files by improving formatting and ensuring consistent use of async session factories.
- Added type hints and improved type safety in various service and test files.
- Adjusted `pyproject.toml` to include configuration for isort, mypy, and ruff for better code quality checks.
- Cleaned up unused imports and organized existing ones in several test files.

app/repositories/task_repo.py

@@ -1,4 +1,5 @@
 """Task repository providing role-aware CRUD helpers."""
+
 from __future__ import annotations
 
 from collections.abc import Mapping, Sequence
@@ -105,7 +106,9 @@ class TaskRepository:
         await self._session.flush()
         return task
 
-    def _apply_filters(self, stmt: Select[tuple[Task]], params: TaskQueryParams) -> Select[tuple[Task]]:
+    def _apply_filters(
+        self, stmt: Select[tuple[Task]], params: TaskQueryParams
+    ) -> Select[tuple[Task]]:
         if params.deal_id is not None:
             stmt = stmt.where(Task.deal_id == params.deal_id)
         if params.only_open: