Adds Prometheus instrumentation across the checkout funnel, auth flow,
Stripe calls, rate limiters, and HTTP middleware (inflight gauge, request
and response sizes). Introduces a slog handler that counts log lines by
level so the dashboard can show error/warn rates; existing log.Printf
calls are routed through slog and counted as info.
Backs the new "terminalshop — Service Overview" Grafana dashboard.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
adds a /pay/{token} redirect endpoint that generates a short URL
pointing to a stripe checkout sessions in setup mode. The TUI shows a QR
code and URL on the payment page so users can add a card via the browser
instead of entering raw card data over SSH.
the checkout.session.completed webhook saves the card to the database.
the TUI polls GET /api/v1/cards every second and auto-proceeds to
confirmation once the new card is detected.
also adds a dev.sh startup script that runs all four required processes.
(SSH server, API server, Stripe CLI listener, ngrok) in a single
terminal
