- Introduced `user_sessions` table with support for per-device authentication sessions.
- Added `UserSession` model, including fields for device metadata, IP, and session state.
- Created schemas (`SessionBase`, `SessionCreate`, `SessionResponse`) to manage session data and responses.
- Implemented utilities for extracting and parsing device information from HTTP requests.
- Added Alembic migration to define `user_sessions` table with indexes for performance and cleanup.
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.
