010106-backend-architecturelisted

# Backend Architecture Standards ## Overview Coding standards for backend module structure, error handling, and API response patterns. ## Quick Reference ### Module Structure Standard module files: - `types.ts` — Interfaces and types - `schemas.ts` — Validation schemas (e.g., Zod) - `constants.ts` — Domain constants - `repository.ts` — Data access (queries + mutations) - `service.ts` — Business logic - `actions.ts` — Server Action entry points - `utils.ts` — Pure helper functions ### Error Handling - Use typed error classes: `HttpError` → `ValidationError`, `UnauthorizedError`, `ForbiddenError`, `NotFoundError` - Structured API response: `{ data, error: { code, message, traceId } }` - Error codes follow `PREFIX_CATEGORY_INDEX` (e.g., `VAL_000_001`) - Database errors mapped to user-friendly messages ### Environment Variables - Centralized `env.ts` with `requireEnv()` for validation - All env vars accessed through this file only - Logs sanitized before output (strip secrets, emails, tokens) ## References - [Error Handling](references/error-handling.md) - [Module Structure](references/module-structure.md) - [Error Codes Format](references/error-codes-format.md) — Structured error codes, prefix conventions, traceId - [Foreign Key Chains](references/foreign-key-chains.md) — Multi-currency FK chain, translation FK chain, FK protection for admin DELETE