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/api/v1/deals.py

@@ -1,4 +1,5 @@
 """Deal API endpoints backed by DealService with inline payload schemas."""
+
 from __future__ import annotations
 
 from decimal import Decimal
@@ -8,7 +9,7 @@ from pydantic import BaseModel
 
 from app.api.deps import get_deal_repository, get_deal_service, get_organization_context
 from app.models.deal import DealCreate, DealRead, DealStage, DealStatus
-from app.repositories.deal_repo import DealRepository, DealAccessError, DealQueryParams
+from app.repositories.deal_repo import DealAccessError, DealQueryParams, DealRepository
 from app.services.deal_service import (
     DealService,
     DealStageTransitionError,
@@ -66,7 +67,9 @@ async def list_deals(
         statuses_value = [DealStatus(value) for value in status_filter] if status_filter else None
         stage_value = DealStage(stage) if stage else None
     except ValueError as exc:
-        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Invalid deal filter") from exc
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST, detail="Invalid deal filter"
+        ) from exc
 
     params = DealQueryParams(
         organization_id=context.organization_id,
@@ -96,7 +99,9 @@ async def create_deal(
 ) -> DealRead:
     """Create a new deal within the current organization."""
 
-    data = payload.to_domain(organization_id=context.organization_id, fallback_owner=context.user_id)
+    data = payload.to_domain(
+        organization_id=context.organization_id, fallback_owner=context.user_id
+    )
     try:
         deal = await service.create_deal(data, context=context)
     except DealAccessError as exc: