Cs Feat Impl

This is the implementation phase of a three-stage feature workflow. It picks up after design approval, working through paradigm-based steps (routing, compute, persistence, tests) defined in a checklist file. The core discipline is stopping when you hit anything the design didn't cover rather than improvising patches. It enforces boundaries hard: no touching neighbor code, no inventing concepts absent from the design doc's term list, no merging steps. Every finish gets a structured report listing files changed, functions touched, and how each acceptance scenario maps to evidence. The reflection checks catch AI drift patterns like growing util files or adding fourth parameters. Treats the approved design as a contract, not a suggestion.