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/activity.py

@@ -1,4 +1,5 @@
 """Activity timeline ORM model and schemas."""
+
 from __future__ import annotations
 
 from datetime import datetime
@@ -6,10 +7,12 @@ from enum import StrEnum
 from typing import Any
 
 from pydantic import BaseModel, ConfigDict, Field
-from sqlalchemy import DateTime, Enum as SqlEnum, ForeignKey, Integer, func, text
+from sqlalchemy import DateTime, ForeignKey, Integer, func, text
+from sqlalchemy import Enum as SqlEnum
 from sqlalchemy.dialects.postgresql import JSONB
-from sqlalchemy.types import JSON as GenericJSON, TypeDecorator
 from sqlalchemy.orm import Mapped, mapped_column, relationship
+from sqlalchemy.types import JSON as GenericJSON
+from sqlalchemy.types import TypeDecorator
 
 from app.models.base import Base, enum_values
 
@@ -44,10 +47,12 @@ class Activity(Base):
     id: Mapped[int] = mapped_column(Integer, primary_key=True)
     deal_id: Mapped[int] = mapped_column(ForeignKey("deals.id", ondelete="CASCADE"))
     author_id: Mapped[int | None] = mapped_column(
-        ForeignKey("users.id", ondelete="SET NULL"), nullable=True
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
     )
     type: Mapped[ActivityType] = mapped_column(
-        SqlEnum(ActivityType, name="activity_type", values_callable=enum_values), nullable=False
+        SqlEnum(ActivityType, name="activity_type", values_callable=enum_values),
+        nullable=False,
     )
     payload: Mapped[dict[str, Any]] = mapped_column(
         JSONBCompat().with_variant(GenericJSON(), "sqlite"),
@@ -55,7 +60,9 @@ class Activity(Base):
         server_default=text("'{}'"),
     )
     created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now(), nullable=False
+        DateTime(timezone=True),
+        server_default=func.now(),
+        nullable=False,
     )
 
     deal = relationship("Deal", back_populates="activities")