# Global Project Constraints

1. **Language Requirements**: 
   - All code comments **MUST** be written in **English**.
   - All server and client logs (`console.log`, `logger.info`, `logger.error`, etc.) **MUST** be written in **English**.

2. **Internationalization (i18n)**:
   - All user-facing messages, API response messages, error messages, and UI text **MUST** guarantee internationalization support.
   - Do not use hardcoded string literals for messages. Always use the project's designated i18n service or translation utility with proper keys.

3. **UI Notifications**:
   - All popup messages, error alerts, and system notifications **MUST** uniformly use the toast component (e.g., via `useToast().showError()`, `showSuccess()`). 
   - Never use native browser `window.alert()`.
