08 — Billing (Packages)

Model: one-off purchases of event packages (Endkunden) or annual subscriptions (Reseller); see 15-packages-design.md for details.
Tables: packages, event_packages, tenant_packages, package_purchases (see 04-data-model-migrations.md and 15-packages-design.md).
Providers: Stripe (server-side checkout + webhooks for Einmalkäufe/Subscriptions); store receipts.
Idempotency: purchase intents keyed; purchase writes idempotent; retries safe.
Limits: Enforce package selection at event creation; check event-specific limits (e.g. max_photos) during usage; tenant limits for reseller event count.