Refactor: Stripe Handling + New ULTRA Plan

[1orZero]

• removed the meta data support in Stripe (plan_code / planGivenWeeks)
• Re-factor the Stripe webhook implementation
• Allow user to Upgrade or Downgrade plan (Show modal popup and operate manually by us)
• All production/staging stripe payment links has been created
• We now have a central configuration file to manage all Stripe products stripe_config.ts

[1orZero]

Test Payment Flow for Cypress

Steps

1. Make sure the user is on Free plan.
2. Cypress calls the /api/cypress/test-payment-event endpoint to start the test.
   • The endpoint will send a stripe webhook to the /api/webhooks/stripe endpoint.
3. The webhook will update the user's subscription plan to pro-monthly.
4. Cypress refreshes the page and checks if the user is on Pro plan.
5. After each test, Cypress call a /api/cypress/reset-test-payment-user-subscription endpoint to reset the user's subscription plan to free.

TODOs

• Pass the current vercel url to the cypress test
• create api endpoint to trigger stripe webhook api/cypress/test-payment-event
• create api endpoint to reset user's subscription plan
• create the test

Changes

• Add new API route api/cypress/test-payment-event to trigger stripe webhook
• Add new API route api/cypress/reset-test-payment-user-subscription to reset user's subscription plan
• Add new test cypress/e2e/payment.cy.ts to test the payment flow