PR #8257 - speakeasy-api/gram

Summary

Revert #7459 (9b80ab11601ee63da82b60b382e8bbf18be80a8b) and restore hosted Stripe checkout.
Remove the embedded form and its new publishable-key requirement, preserving subsequent changes.
Follow up on the production image rollback in speakeasy-api/gram-infra#4796 so subsequent releases do not reintroduce the regression.

Motivation

The embedded checkout migration requires STRIPE_PUBLISHABLE_KEY, but the deployment configuration did not wire it into the server. Restore the previous checkout flow while the configuration and rollout are addressed.

Validation

Verified the staged diff exactly matched the inverse of #7459.
mise run test:server ./internal/thirdparty/stripe/: 129 tests passed.
Diff and pre-commit checks passed. No database migrations changed.
End-to-end checkout has not yet been verified.

Gutternote review steps

Use a sandbox organization with self-serve billing enabled, no active subscription, and an org-admin session.
Open Billing and start checkout.
Verify checkout redirects to Stripe-hosted Checkout rather than mounting an embedded form.
Complete checkout using sandbox payment details and verify the dashboard reflects the subscription after webhook processing.

Summary by cubic

Reverts the embedded Stripe checkout migration from #7459 and restores the hosted flow, since deployment configuration never wired the required STRIPE_PUBLISHABLE_KEY.

Rollback details

Checkout redirects to Stripe-hosted Checkout again instead of mounting an inline form.
Removes the STRIPE_PUBLISHABLE_KEY requirement, the checkout status polling endpoint, and the embedded checkout UI.
Complete the production image rollback in speakeasy-api/gram-infra#4796 before future releases to avoid reintroducing this regression.

🚀 Preview Environment (PR #8257)

Preview URL: https://pr-8257.dev.getgram.ai

Component	Status	Details	Updated (UTC)
✅ Database	Ready	Created and validated	2026-10-29 01:23:23.
✅ Images	Available	Container images ready	2026-10-29 01:25:00.

_{Gram Preview Bot}