Add Stripe embedded onboarding

- Update StripeConnectOnboarding component with embedded flow
- Add new Stripe routes and service methods for embedded onboarding
- Update EarningsStatus and EarningsDashboard to support new flow
- Add required frontend dependencies

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/package.json

@@ -4,6 +4,8 @@
   "private": true,
   "dependencies": {
     "@googlemaps/js-api-loader": "^1.16.10",
+    "@stripe/connect-js": "^3.3.31",
+    "@stripe/react-connect-js": "^3.3.31",
     "@stripe/react-stripe-js": "^3.3.1",
     "@stripe/stripe-js": "^5.2.0",
     "@testing-library/dom": "^10.4.0",