fix: accept both owner names in attribution checks

[nothingnesses]

Problem

GitHub used the owner's public display name for PR #9's squash commit. The attribution check accepted only the local Git name, so main CI failed despite an unchanged file tree.

Change

• Accept exactly nothingnesses or Jesse Abadilla with 18732253+nothingnesses@users.noreply.github.com.
• Retain the complete-history scan and raw-identity checks.
• Retain all attribution-text prohibitions.
• Add seven regression cases for the approved identities and rejected variants.
• Record this CI repair as active work and preserve adoption as pending work.

Existing commits and GitHub settings remain unchanged.

Validation

• All 50 attribution fixtures passed.
• Host just ci passed before and after the local commit.
• The committed tree matches the reviewed tree.

Failure: https://github.com/nothingnesses/agent-flow/actions/runs/35285915117/job/105418071892.