[grade=B] Make website billing production-ready

IMPLEMENTATION_PLAN.md

@@ -34,9 +34,9 @@ Paid subscriptions unlock:
 - `swarm`
 
 ### Stripe plans
-- 1 month — $25
+- 1 month — $20
 - 3 months — $50
-- 6 months — $65
+- 6 months — $70
 - 12 months — $99
 
 ### Subscription policy
@@ -78,7 +78,8 @@ Source of truth for:
 ## Proposed API surface
 
 ### Public endpoints for website
-- `POST /api/checkout/session`
+- `POST /api/checkout/one-time`
+- `POST /api/checkout/subscription`
 - `GET /api/public/plans`
 
 ### DashCaddy app endpoints
@@ -200,7 +201,7 @@ On cancellation:
 
 The `dashcaddy.net` marketing site should be updated to:
 - add Premium pricing section buttons
-- each button POSTs to `/api/checkout/session` with a plan code
+- each button POSTs to `/api/checkout/{one-time,subscription}` with a plan code
 - redirect to returned Stripe Checkout URL
 - success page explains license delivery/activation flow
 - cancellation page returns user to pricing
@@ -223,7 +224,7 @@ Initial env expected:
 1. Scaffold Node service for `dashcaddy-license-server`
 2. Add Stripe SDK, Express, and SQLite/Postgres adapter layer
 3. Build `/api/public/plans`
-4. Build `/api/checkout/session`
+4. Build `/api/checkout/one-time` and `/api/checkout/subscription`
 5. Build `/api/stripe/webhook`
 6. Port/reuse DashCaddy-compatible license generation/validation helpers
 7. Build `/api/license/validate`