app/square.py (Terminal Checkout API: device-code pairing, create/poll/cancel checkout;
creds in vault, device_id in sales_setting). /sales/terminal/{status,pair,pair/{id},
checkout,checkout/{id},checkout/{id}/cancel}. POS: 📟 Terminal payment method (shown when
paired) → pushes total to the terminal, polls, finalises the sale only on COMPLETED;
Settings → Pair a terminal (device-code flow). square_* added to admin Connections.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
