Plan changes via /billing/manage. On upgrade:
- You pay the prorated difference for the remaining billing period immediately.
- Higher limits + features available instantly.
On downgrade:
- Switch happens at the end of the current period (no prorated refund).
- Until then, you keep the higher limits.
Promo codes: enter in the code field on the plans page before upgrading (stored in localStorage) — auto-injected on the next plan click.