- Removed the export of models from the database connection module to simplify the structure.
- Updated various files to import models directly from the new centralized models module.
- Ensured consistency across the codebase by replacing mongoose model references with the new import paths.
* chore: Add deprecation warnings for environment variables in checks
* chore: Change deprecatedVariables to a const declaration in checks.js
* fix: Add date validation in checkBalanceRecord to prevent invalid date errors
* feat: Add setBalanceConfig middleware to synchronize user balance settings
* chore: Reorder middleware imports in oauth.js for better readability
