Tidy: drop two pieces of dead code (#216)

- server/src/routes/checkout.js: remove unused createBillingPortalSession
  from the destructuring import. The portal logic lives in
  routes/billing.js; checkout.js never called it.
- src/background/events.js: remove a stale commented-out
  browser.runtime.openOptionsPage() line.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/src/routes/checkout.js

@@ -1,6 +1,6 @@
 const express = require('express');
 const { requireAuth } = require('../services/jwt');
-const { createCheckoutSession, createBillingPortalSession } = require('../services/stripe');
+const { createCheckoutSession } = require('../services/stripe');
 const { renderPage } = require('../templates');
 
 const router = express.Router();

src/background/events.js

@@ -3,8 +3,6 @@ if (typeof browser === 'undefined') {
   browser = typeof chrome !== 'undefined' ? chrome : null;
 }
 
-// browser.runtime.openOptionsPage();
-
 const uninstallUrl = "http://lawrencehook.com/rys/👋";
 browser.runtime.setUninstallURL(uninstallUrl);