Strict code planning: analyze the code to be touched, name reuse opportunities and abstraction candidates, decide scope through the decision pipeline, and specify the public API and the test plan. Trigger when: the task is to plan code before implementation - analyzing current code, reuse and abstraction opportunities, public API and data shapes, and the test plan at seams. [DO NOT] use for implementing: the plan never writes or edits code; writing tests lives in `pablo-tdd`, refactor methodology in `refactor-identification`, principles in `pablo-code-philosophy`.
