improve-codebase-architecturelisted

# 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. Everything here is built on a shared design vocabulary: - Call the Skill tool with "codebase-design" for the architecture vocabulary (**module**, **interface**, **depth**, **seam**, **adapter**, **leverage**, **locality**) and its principles (the deletion test, "the interface is the test surface", "one adapter = hypothetical seam, two = real"). Use these terms exactly in every suggestion - don't drift into "component," "service," "API," or "boundary." - If the repo keeps a domain glossary, its terms name the good seams; if it keeps decision records, those record decisions this skill should not re-litigate. Read both before scanning, and skip this quietly when the repo has neither. ## Process ### 1. Explore **Scope before you scan - YAGNI.** Deepening a module pays off by making future changes to it easier, so put extra weight on the parts of the codebase that have recently changed. Decide *where* to look before you look: - If the user named a direction - a module, a subsystem, a pain point - take it, and skip the inference below. - Otherwise, walk back a good stretch of the commit history (`git log --oneline`) to find the codebase's hot spots - the files and areas that keep coming up - and let those paths pull your attention first. If the changes are scattered with