POST /ai-sessions/{id}/handoffs/{hid}/claim previously required only an
authenticated user, so a viewer-role account user could claim escalations.
Codex review flagged this as wedge-relevant: the Escalation Mode race-
condition story (two seniors clicking Pick Up simultaneously) depends on
auth gating for audit integrity. Originally captured as a deferred TODO
during /plan-eng-review, then moved in-scope by /codex review.
Swap the dep to require_engineer_or_admin. One-line change. Two new tests:
- viewer_role gets 403 with "Engineer or admin access required"
- engineer/owner role still succeeds and claimed_at + claimed_by populate
Existing handoff create + queue tests unaffected.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>