Start the QR Builder FastAPI server at ~/projects/qrcode — QR generation, image embedding, batch processing, and restyle (change appearance while preserving data). TRIGGER WHEN: 'start the QR builder API', 'run the qrcode server', 'work on the QR builder', 'generate or embed a QR code via the API'. DO NOT USE WHEN: running the QR Builder test suite (use qrcode-test) or doing generic QR work outside this repo.
