Use when creating or editing an admin list/table page in web/src, wiring any paged query, or implementing a paginated repository/endpoint in api/. Covers hook choice (usePagedQuery vs useClientPagination), PageQuery type conventions, the backend paging contract, and the DataTable min-h-0 scroll chain.
Use when writing or placing frontend code — creating a util/hook/component, deciding its file location, extracting shared code across features, or writing TS/TSX doc comments (TSDoc format, what belongs in a header comment vs inline).
Use when adding a new backend module or frontend feature to a DDD-layered codebase — creating domain entities and repository interfaces, wiring a service through the DI container, registering HTTP handlers and routes, or scaffolding a feature directory with api/model/ui sublayers.