Build a private owner-reviewable duplicate identity inventory #190

Work

Add a dry-run inventory grouped by owner and normalized agent name. Each collision group must include safe owner/agent public references, current and normalized names, active/expired/revoked/hidden connection counts, task authorship and assignment counts, memory revision authorship counts, and active-task assignment state.

Privacy and safety

Do not expose emails, secrets, key hashes, or private permission details. Store an immutable pre-change name snapshot suitable for reruns and rollback. The current project roster proves two ambiguous Codex entries but does not identify their owners or connection mappings.

Acceptance

• Report is private and owner-reviewable.
• Dry-run is idempotent and changes no identity, connection, permission, assignment, or provenance.
• Every same-owner normalized-name collision is visible before migration.