Orchestrates the full greenfield Python pipeline in order: scaffold → architecture → TDD → optional performance → validation. Use this when the user wants to build a new Python project end-to-end, asks to run the full pipeline, or runs /greenfield-orchestrator. Requires requirements and acceptance criteria up front. Gates every phase transition on the previous phase's verified exit condition — never advances on assumption. Use proactively when starting any new Python project from scratch.
