## The two places that change

**The checkout session.** A subscription session uses subscription mode and a recurring price. A
one-time session uses payment mode and a one-time price. That is a parameter in the billing adapter,
not a different integration.

**What entitlement means.** `app/models/entitlement.rb` holds one line that decides:

```ruby
def for(account) = Subscription.new(account)
```

For a permanent purchase, the strategy reads a paid-once record rather than a subscription status.
The file ships with several strategies and a comment saying it is a file you edit rather than a
framework to extend, which is exactly what this change is.

## What does not change

Every controller with `include RequireEntitlement`. That is the reason the seam exists: the gate and
the meaning of the gate are separate, so switching your business model does not mean auditing
controllers to find the ones that gate.

The webhook handling changes shape, though. One-time payments produce
`checkout.session.completed` and `charge.refunded`, and no invoice or subscription events at all. So
the renewal and cancellation branches simply stop firing.

## Refunds are the part to think about

A subscription that stops renewing needs no decision. A permanent purchase that gets refunded does:
the money went back, and the account still has the record that entitles it. Handle `charge.refunded`
and revoke, or you are giving the product away to anyone who asks their bank.

## This site does both

shiponeshot.com sells a one-time license and runs the subscription flow the kit ships with, which is
why both paths exist in the codebase. `config/routes.rb` shows the split: the subscription routes and
the kit purchase routes live side by side.

## Verify before you charge

```bash
bin/check
```

Then run the flow against a test-mode key and refund the charge in the dashboard. If the account
still has access after the refund, the revoke branch is not wired, and you want to find that out now.