Improve Codebase Architecture Surface architectural friction and propose deepening opportunities — refactors that turn shallow modules into deep ones. The aim is testability and AI-navigability. Glossary Use these terms exactly in every suggestion. Consistent language is the point — don't drift into "component," "service," "API," or "boundary." Full definitions in LANGUAGE.md. - Module — anything with an interface and an implementation (function, class, package, slice). - Interface — everything a caller must know to use the module: types, invariants, error modes, ordering, config. Not just th…