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/contact_repo.py

@@ -1,4 +1,5 @@
 """Repository helpers for contacts with role-aware access."""
+
 from __future__ import annotations
 
 from collections.abc import Mapping, Sequence
@@ -44,7 +45,9 @@ class ContactRepository:
         role: OrganizationRole,
         user_id: int,
     ) -> Sequence[Contact]:
-        stmt: Select[tuple[Contact]] = select(Contact).where(Contact.organization_id == params.organization_id)
+        stmt: Select[tuple[Contact]] = select(Contact).where(
+            Contact.organization_id == params.organization_id
+        )
         stmt = self._apply_filters(stmt, params, role, user_id)
         offset = (max(params.page, 1) - 1) * params.page_size
         stmt = stmt.order_by(Contact.created_at.desc()).offset(offset).limit(params.page_size)
@@ -59,7 +62,9 @@ class ContactRepository:
         role: OrganizationRole,
         user_id: int,
     ) -> Contact | None:
-        stmt = select(Contact).where(Contact.id == contact_id, Contact.organization_id == organization_id)
+        stmt = select(Contact).where(
+            Contact.id == contact_id, Contact.organization_id == organization_id
+        )
         result = await self._session.scalars(stmt)
         return result.first()
 
@@ -117,7 +122,7 @@ class ContactRepository:
             pattern = f"%{params.search.lower()}%"
             stmt = stmt.where(
                 func.lower(Contact.name).like(pattern)
-                | func.lower(func.coalesce(Contact.email, "")).like(pattern)
+                | func.lower(func.coalesce(Contact.email, "")).like(pattern),
             )
         if params.owner_id is not None:
             if role == OrganizationRole.MEMBER: