fix: restore stripe mount for checkout while keeping webhook raw body

Need BOTH mounts:
- /stripe/webhook (line 43, BEFORE json parser) - raw body for signature
- /stripe (line 83, AFTER json parser) - parsed body for checkout

This allows:
- Webhook at /stripe/webhook with raw body
- Checkout at /stripe/create-checkout-session with parsed body

Signed-off-by: Claude (Chronicler #57) <claude@firefrostgaming.com>

services/arbiter-3.0/src/index.js

@@ -80,6 +80,7 @@ const csrfProtection = csrf({ cookie: false });
 app.use('/auth', authRoutes);
 app.use('/admin', csrfProtection, adminRoutes);
 app.use('/webhook', webhookRoutes);
+app.use('/stripe', stripeRoutes); // Checkout and portal routes (uses JSON body)
 
 // Start Application
 const PORT = process.env.PORT || 3500;