feat(payment): regional pricing, Stripe price id, OAuth domain (→ main)

[rdahis]

Reconstructs the payment/account work onto main.

These commits were originally pushed to staging under the old workflow. staging is
scheduled to be reset to main, so they have been cherry-picked onto a branch cut from
main per the current Git Flow.

What's here

• feat: expose the Stripe price id on StripePriceNode #1044 expose the Stripe price id on StripePriceNode
• fix(account): return Google OAuth to the originating frontend domain #1046 return Google OAuth to the originating frontend domain
• feat(payment): charge card-country regional price at checkout #1045 charge the card-country regional price at checkout (trial path)
• refactor(account): remove legacy Career.team_old and role_old fields #1048 remove legacy Career.team_old / role_old

Two further staging-only commits (the convert_form_field graphql fix and #1038 spatial
coverage) are already on main under different SHAs — cherry-picking them came out empty,
so they are correctly omitted.

Heads-up for the deploy

• Carries a migration: account/0029_remove_career_team_old_remove_career_role_old — it
  drops two columns. Chain is intact; its dependency 0028_alter_account_uuid is already on main.
• main does not yet have the product-aware webhook refactor that exists on staging. The
  regional-pricing hook applied cleanly into setup_intent_succeeded, but CI (especially
  test_regional_pricing.py) is the real check, since a clean cherry-pick is textual, not semantic.
• Enforcement fails safe by design: on any uncertainty it keeps the original price rather than
  blocking checkout.

Deploy order

Merge and deploy before the website PR of the same name.