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/models/deal.py

@@ -1,4 +1,5 @@
 """Deal ORM model and schemas."""
+
 from __future__ import annotations
 
 from datetime import datetime
@@ -6,7 +7,8 @@ from decimal import Decimal
 from enum import StrEnum
 
 from pydantic import BaseModel, ConfigDict
-from sqlalchemy import DateTime, Enum as SqlEnum, ForeignKey, Integer, Numeric, String, func
+from sqlalchemy import DateTime, ForeignKey, Integer, Numeric, String, func
+from sqlalchemy import Enum as SqlEnum
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from app.models.base import Base, enum_values
@@ -49,10 +51,15 @@ class Deal(Base):
         default=DealStage.QUALIFICATION,
     )
     created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now(), nullable=False
+        DateTime(timezone=True),
+        server_default=func.now(),
+        nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now(), onupdate=func.now(), nullable=False
+        DateTime(timezone=True),
+        server_default=func.now(),
+        onupdate=func.now(),
+        nullable=False,
     )
 
     organization = relationship("Organization", back_populates="deals")