- Inject umbral_name into shared_fields for umbral contacts (always visible)
- Show @umbralname subtitle in detail panel header
- Add preferred_name to panel fields with synced label for umbral contacts
- Add Link button on standard contacts to tie to umbral user via connection request
- Migration 046: person_id FK on connection_requests with index
- Validate person_id ownership on send, re-validate + convert on accept
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>