MUST: Proficiency using AI-assisted engineering tools (e.g., Claude Code, GitHub Copilot) to accelerate implementation, refactoring, test creation, and debugging—while validating correctness and adhering to secure handling practices. Deep experience with modern front-end tooling: Vite/Webpack, Babel/SWC, npm/pnpm/yarn, monorepos (optional), and build/release pipelines.