invoice-app-1

React SPA codebase architecture guide. Use when scaffolding a new feature, placing files, wiring up an API hook, adding a Zustand store, protecting a route, handling errors, or optimising performance. Covers the complete vertical slice from API to UI using a feature-driven architecture. Triggers on any task involving project structure, API design, state management, security, components, error handling, performance, deployment, or testing in a React + Vite + React Query codebase.