* chore: Add mathjs dependency
* refactor: Replace eval with mathjs for safer expression evaluation and improve session expiry handling to not environment variables from data-schemas package
* test: Add integration tests for math function with environment variable expressions
* refactor: Update test description for clarity on expiresIn behavior
* refactor: Update test cases to clarify default expiration behavior for token generation
* refactor: Improve error handling in math function for clearer evaluation errors
* fix: add undefined password check in local user authentication
* fix: edge case - issue deleting user when no conversations in deleteUserController
* feat: Integrate Mailgun API for email sending functionality
* fix: undefined SESSION_EXPIRY handling and add tests
* fix: update import path for isEnabled utility in azureUtils.js to resolve circular dep.
