[swibi-ttd]

Summary

• make the Sigstore certificate identity policy case-insensitive because GitHub emits lowercase repository identities
• retain the existing restriction to uid2-shared-actions and the calling repository
• add regression coverage for lowercase and uppercase valid identities plus unrelated repositories

Verification

• bash actions/attest_image/tests/test_identity_regex.sh
• bash actions/shared_publish_to_docker/tests/test_validate_vuln_floor.sh
• bash -n actions/attest_image/tests/test_identity_regex.sh
• git diff --check
• independently verified the failed uid-reverse-proxy digest with the case-insensitive policy

Evidence

• Failing release: https://github.com/IABTechLab/uid2-examples/actions/runs/35563729206
• Jira: https://thetradedesk.atlassian.net/browse/UID2-7932

[swibi-ttd]

Superseded by IABTechLab/uid2-examples#222. We are normalizing the caller workflow references under UID2-7920 and keeping the shared attestation identity policy strict.