Why: Clock-derived IDs could collide and string-scoped hosts could impersonate a registered audit publisher.
Evidence: Fixed-clock concurrent, ambiguous private offset, forged scoped-host, and registered publisher RED-to-GREEN tests; go test ./... -count=1 and targeted race test passed locally as SELF.
Impact: Generate 192-bit host IDs, reject ambiguous explicit offsets, and issue a publication-only capability at verifier registration.
Refs: Stage 5 W9; approved Stage 6 audit-link design adjustment r1; review of a8fa2fe