- Moved SQL queries from multiple worker files into `src/worker/sql.rs` for better organization and maintainability.
- Updated references in `stockage_manager.rs`, `transport.rs`, `underground.rs`, `user_character.rs`, and `value_recalculation.rs` to use the new centralized SQL queries.
- Improved code readability by replacing `.get(0)` with `.first()` for better clarity when retrieving the first row from query results.
- Cleaned up unnecessary comments and consolidated related SQL queries.