Add pyproject.toml for consolidated project configuration and replace Black, isort, and Flake8 with Ruff

- Introduced `pyproject.toml` to centralize backend tool configurations (e.g., Ruff, mypy, coverage, pytest).
- Replaced Black, isort, and Flake8 with Ruff for linting, formatting, and import sorting.
- Updated `requirements.txt` to include Ruff and remove replaced tools.
- Added `Makefile` to streamline development workflows with commands for linting, formatting, type-checking, testing, and cleanup.

backend/app/models/user_session.py

@@ -6,7 +6,10 @@ This allows users to:
 - Logout from specific devices
 - Manage their active sessions
 """
-from sqlalchemy import Column, String, Boolean, DateTime, ForeignKey, Index
+
+from datetime import UTC
+
+from sqlalchemy import Boolean, Column, DateTime, ForeignKey, Index, String
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
 
@@ -20,19 +23,27 @@ class UserSession(Base, UUIDMixin, TimestampMixin):
     Each time a user logs in from a device, a new session is created.
     Sessions are identified by the refresh token JTI (JWT ID).
     """
-    __tablename__ = 'user_sessions'
+
+    __tablename__ = "user_sessions"
 
     # Foreign key to user
-    user_id = Column(UUID(as_uuid=True), ForeignKey('users.id', ondelete='CASCADE'), nullable=False, index=True)
+    user_id = Column(
+        UUID(as_uuid=True),
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
 
     # Refresh token identifier (JWT ID from the refresh token)
     refresh_token_jti = Column(String(255), unique=True, nullable=False, index=True)
 
     # Device information
     device_name = Column(String(255), nullable=True)  # "iPhone 14", "Chrome on MacBook"
-    device_id = Column(String(255), nullable=True)    # Persistent device identifier (from client)
-    ip_address = Column(String(45), nullable=True)    # IPv4 (15 chars) or IPv6 (45 chars)
-    user_agent = Column(String(500), nullable=True)   # Browser/app user agent
+    device_id = Column(
+        String(255), nullable=True
+    )  # Persistent device identifier (from client)
+    ip_address = Column(String(45), nullable=True)  # IPv4 (15 chars) or IPv6 (45 chars)
+    user_agent = Column(String(500), nullable=True)  # Browser/app user agent
 
     # Session timing
     last_used_at = Column(DateTime(timezone=True), nullable=False)
@@ -50,8 +61,8 @@ class UserSession(Base, UUIDMixin, TimestampMixin):
 
     # Composite indexes for performance (defined in migration)
     __table_args__ = (
-        Index('ix_user_sessions_user_active', 'user_id', 'is_active'),
-        Index('ix_user_sessions_jti_active', 'refresh_token_jti', 'is_active'),
+        Index("ix_user_sessions_user_active", "user_id", "is_active"),
+        Index("ix_user_sessions_jti_active", "refresh_token_jti", "is_active"),
     )
 
     def __repr__(self):
@@ -60,21 +71,24 @@ class UserSession(Base, UUIDMixin, TimestampMixin):
     @property
     def is_expired(self) -> bool:
         """Check if session has expired."""
-        from datetime import datetime, timezone
-        return self.expires_at < datetime.now(timezone.utc)
+        from datetime import datetime
+
+        return self.expires_at < datetime.now(UTC)
 
     def to_dict(self):
         """Convert session to dictionary for serialization."""
         return {
-            'id': str(self.id),
-            'user_id': str(self.user_id),
-            'device_name': self.device_name,
-            'device_id': self.device_id,
-            'ip_address': self.ip_address,
-            'last_used_at': self.last_used_at.isoformat() if self.last_used_at else None,
-            'expires_at': self.expires_at.isoformat() if self.expires_at else None,
-            'is_active': self.is_active,
-            'location_city': self.location_city,
-            'location_country': self.location_country,
-            'created_at': self.created_at.isoformat() if self.created_at else None,
+            "id": str(self.id),
+            "user_id": str(self.user_id),
+            "device_name": self.device_name,
+            "device_id": self.device_id,
+            "ip_address": self.ip_address,
+            "last_used_at": self.last_used_at.isoformat()
+            if self.last_used_at
+            else None,
+            "expires_at": self.expires_at.isoformat() if self.expires_at else None,
+            "is_active": self.is_active,
+            "location_city": self.location_city,
+            "location_country": self.location_country,
+            "created_at": self.created_at.isoformat() if self.created_at else None,
         }