codebase-designlisted

# Codebase Design Supply design discipline within `aaaav-do`. Direct source-changing requests enter that lifecycle first; return decisions to its `design.md`. ## Vocabulary - **Module:** an interface plus its implementation, at any scale. - **Interface:** everything a caller must know, including invariants, ordering, errors, configuration, and performance characteristics. - **Depth:** useful behavior delivered per unit of interface burden. - **Seam:** where behavior can vary without editing the caller. - **Adapter:** a concrete implementation occupying a seam. - **Leverage:** capability reused by callers through a small interface. - **Locality:** change, knowledge, bugs, and proof concentrated behind that interface. Use these terms consistently in the design artifact. `domain-modeling` owns semantic meaning, ubiquitous language, contexts, and invariants. This skill owns the interface and seam shape that contains them. ## Design checks 1. Place the seam at an existing architectural boundary when it fits; introduce a new seam only for real variation. One adapter is usually hypothetical; two adapters demonstrate variation. 2. Minimize what callers must know. Hide invariants and workflow complexity behind the interface instead of distributing them across call sites. 3. Apply the deletion test: removing a useful module should redistribute its complexity to callers. If complexity disappears, the module is probably a pass-through. 4. Make the public interfa