- Deleted outdated backend test cases (`test_auth.py`, `test_rate_limiting.py`, `test_users.py`) to clean up deprecated test structure.
- These tests are now redundant with newer async test implementations and improved coverage.
- Introduced session management endpoints to list, revoke, and cleanup sessions per user.
- Added cron-based job for periodic cleanup of expired sessions.
- Implemented `CRUDSession` for session-specific database operations.
- Integrated session cleanup startup and shutdown events in the application lifecycle.
- Enhanced CORS configuration to include `X-Device-Id` for session tracking.
- Added comprehensive integration tests for multi-device login, per-device logout, session listing, and cleanup logic.
This commit introduces a suite of tests for user models, schemas, CRUD operations, and authentication services. It also adds utilities for in-memory database setup to support these tests and updates environment settings for consistency.
