Upgraded the Stripe SDK from v78 to v83 in go.mod and go.sum, and
updated
all code references to match the new API. Refactored session creation to
use the new method signatures and types. Adjusted tests and
documentation
to reflect the updated dependency and API usage.
- Integrate Stripe Go SDK and implement a checkout service for creating
Stripe Checkout sessions for a demo product.
- Add request/response types for checkout sessions.
- Create HTTP handler for /api/checkout to initiate sessions via POST.
- Provide comprehensive unit tests for Stripe client and web handler.
- Wire Stripe-backed endpoint in server setup.
