sdlc-implement

# sdlc-implement **Executor resolution (host-aware):** - **Claude Code + `superpowers` installed** → prefer **`superpowers:test-driven-development`** + **`superpowers:executing-plans`** (their richer versions; where subagents exist, `superpowers:subagent-driven-development`). - **Otherwise** (Cursor / any host / no companion) → use this. Same discipline, portable. Two things happen in this phase: **build test-first**, and **execute the plan step by step**. ## Test-first (TDD) **No production code without a failing test first.** If you didn't watch the test fail, you don't know it tests the right thing. Wrote code before the test? Delete it and re-derive from the test. **Red → Green → Refactor**, one behavior at a time: 1. **RED** — write the smallest test for the next behavior. Run it. **Watch it fail for the right reason** (it asserts the behavior — not a typo or an import error). 2. **GREEN** — write the *minimal* code to pass. Run it. All green. 3. **REFACTOR** — clean up while staying green. Skip TDD only for throwaway prototypes / generated code / config — and say so. ## Test behavior, not plumbing (anti-patterns to avoid) - **Don't test the mock** — assert real behavior/output, not that a stub was called. - **No test-only methods in production code** — tests exercise the real interface. - **Don't mock what you don't understand** — a wrong mock passes a wrong test. - **Don't leave integration as an afterthought** — cover the real seams, not just isolated uni...