Use CMS Certificate Title for program verifiable credentials

[zamanafzal]

What are the relevant tickets?

Follow-up to the certificate-title work (hq#11907, tracked in hq#11938).

Description

When a program certificate is issued, the verifiable credential (Open Badge) is signed with a name. Today that name is the program title. This changes it to the CMS "Certificate Title" (CertificatePage.product_name) so the issued credential matches the title printed on the certificate (and shown on the MIT Learn certificate page).

Falls back to the program title when product_name is unset.

• Going forward only. This affects credentials signed after this lands. Already-signed verifiable credentials are not re-issued (per product direction on #11938).

Change

courses/api.py — get_verifiable_credentials_payload, program branch:

certificate_name = certificate_page.product_name or certificate.program.title

certificate_page is always present here (the caller returns early via should_provision_verifiable_credential when it is None).

How to test

Manual:

docker compose exec web python manage.py shell

from courses.models import ProgramCertificate
from courses.api import get_certificate_page, get_verifiable_credentials_payload

# pick a cert whose program has a CMS certificate page + the user has an enrollment
cert = ProgramCertificate.objects.first()
page = get_certificate_page(cert)
print("Certificate Title (product_name):", repr(page.product_name))
print("Program title               :", repr(cert.program.title))

payload = get_verifiable_credentials_payload(cert, page)
ach = payload["credentialSubject"]["achievement"]
print("VC name       :", ach["name"])         # -> should be the Certificate Title
print("VC description:", ach["description"])

Automated:

docker compose run --rm web uv run pytest courses/api_test.py -k verifiable_credential

• test_program_certificate_verifiable_credentials_signing_payload now sets a CMS product_name ("Universal AI") distinct from the program title ("Data Science MicroMasters") and asserts the credential name/description use the product_name.
• test_program_verifiable_credential_name_falls_back_to_program_title (new) asserts the fallback to program title when product_name is empty.

Manual (optional): issue a new program certificate for a program whose CMS certificate page "Certificate Title" differs from its program title, then inspect the resulting verifiable credential — credentialSubject.achievement.name should be the Certificate Title.

[github-actions]

OpenAPI Changes

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## Changes for v0.yaml:
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Unexpected changes? Ensure your branch is up-to-date with main (consider rebasing).

[annagav]

So are we giving higher precedence to product name over the program title?

[annagav]

oh, I see

[annagav]

👍

[zamanafzal]

Verified the changes on RC and left a comment on the ticket https://github.com/mitodl/hq/issues/11938#issuecomment-5215132791