Enhance ESLint configuration and improve code consistency

- Added '@typescript-eslint/no-unused-vars' rule to ESLint configuration for better variable management in TypeScript files.
- Updated database.ts to ensure consistent logging format.
- Refactored AuthController and CashflowController to improve variable naming and maintainability.
- Added spacing for better readability in multiple controller methods.
- Adjusted error handling in middleware and repository files for improved clarity.
- Enhanced various service and repository methods to ensure consistent return types and error handling.
- Made minor formatting adjustments across frontend components for improved user experience.

backend-api/src/controllers/DebtCategoryController.ts

@@ -49,10 +49,12 @@ export class DebtCategoryController {
 
     if (withStats === 'true') {
       const categories = await this.categoryService.getWithStats(userId);
+
       return reply.send({categories});
     }
 
     const categories = await this.categoryService.getAllByUser(userId);
+
     return reply.send({categories});
   }