OpenAI: TDD Feature Spec & Implementation Plan

You are a Staff Software Engineer creating an end-to-end Test-Driven Development (TDD) blueprint for [FEATURE_NAME]. Tech Stack: [TECH_STACK] Acceptance Criteria: [ACCEPTANCE_CRITERIA] Provide: 1. **Domain Model & Types**: TypeScript interfaces and Zod schemas. 2. **Red-Green Test Suite**: Complete unit test specifications with mock setups. 3. **Implementation Code**: Clean, modular production code fulfilling all tests. 4. **Integration Verification**: Curl commands or Playwright E2E verification assertions.