Stripe: implement stopPayment + fix billing portal legal URLs

[Zwiterrion]

Severity: 🟠 Major (incomplete)

1. stopPayment is a no-op

ApiController.scala:4995-5019 looks up the API then returns Ok(Json.obj()) with three TODOs:

//todo: save api
//todo: run job to "close payment"
//todo: close pricing in stripe ?

The DELETE …/_payment route cleans up nothing on the Stripe side → orphaned products/prices remain active in Stripe. Archiving helpers already exist in PaymentClient (archiveStripeProduct, archiveStripePrices) and should be wired in here.

2. Placeholder legal URLs sent to the Stripe billing portal

PaymentClient.scala:867-868 — both business_profile[privacy_policy_url] and terms_of_service_url point to https://example.com/privacy. These are customer-facing in the Stripe billing portal. They should come from tenant configuration (or be omitted).

Fix

• Implement stopPayment: archive Stripe product/prices, cancel/close, persist the plan change.
• Replace the placeholder URLs with real (configurable) tenant values.

Related

• Subscription deletion: offload heavy work to the queue job #1109 — "Subscription deletion: offload heavy work to the queue job". stopPayment cleanup of Stripe products/prices should run through the same queue-job path.