tdd-implement

# TDD & Incremental Implementation (`tdd-implement`) ## Overview Build in thin **vertical slices** (from DB to UI) and drive every implementation with tests (**TDD**). Avoid implementing an entire feature or rewriting an entire file in one pass. Each increment should leave the system in a working, testable, and committable state. ## 🔄 The Implementation Loop Execute this loop for *every single task or slice* you implement: 1. **Scope Selection:** Pick the smallest complete piece of functionality (e.g., a single vertical slice). 2. **Stack Discovery:** Identify the repository's test and build commands. - *Tip:* Prefer checked-in wrappers (e.g., `./gradlew` instead of `gradle`). If unsure, check CI workflows (e.g., `.github/workflows/`) to see how the server runs tests. Do not assume defaults like `npm test`. 3. **RED (Failing Test):** Write a failing test at a public interface (seam). A test that passes immediately proves nothing. - *For Bug Fixes (Prove-It Pattern):* Start by writing a test that reproduces the bug (it must fail) before touching production code. **Tip:** For complex bugs, you may `invoke_subagent` to write this failing test to ensure it is written strictly without bias or knowledge of the incoming fix. 4. **GREEN (Implementation):** Write the *simplest, most minimal* code required to make the test pass. 5. **VERIFY:** Run the focused test to ensure it passes, then run the full test suite to check for regressions. You MUST also run the build comman...