tdd

> Ported from oh-my-codex `tdd`. OMX runtime conventions (`$macro` invocation, `omx` CLI, `.omx/` state directory) are replaced with WorkBuddy idioms (Skill tool, Agent tool, task list, `.workbuddy/memory`). # TDD — deprecated Hard-deprecated as a standalone skill. Do not invoke or route this skill. Keep test-first discipline inside the active implementation workflow (the `plan` skill and normal implementation flow). The discipline is the value; here it is for reference: **The Iron Law:** NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST. Write code before the test? Delete it and start over. **Red-Green-Refactor cycle:** 1. **RED** — Write the next failing test; run it; it MUST fail. If it passes, the test is wrong. 2. **GREEN** — Write only enough code to pass. No extras. Run; it MUST pass. 3. **REFACTOR** — Improve quality; run tests after every change; must stay green. 4. **REPEAT** — Next failing test. **Enforcement:** code-before-test → stop and write the test; test-passes-first → fix it to fail; multiple features per cycle → one test, one feature; skipping refactor → go back and clean up. For durable multi-goal execution that should keep this discipline, use `ultragoal`; for the implementation workflow itself, use `plan`.