PUT /api/persons/{id}/relationships/{relId} (@RequirePermission WRITE_ALL)
updates a relationship's type, related person, dates and notes in place,
preserving the original createdAt. The update re-runs every create invariant —
self-relation (VALIDATION_ERROR), date coherence/order, reverse PARENT_OF
(CIRCULAR_RELATIONSHIP) and the (person, relatedPerson, type) unique constraint
via saveAndFlush (DUPLICATE_RELATIONSHIP) — and re-flags both endpoints as
family members when edited into a family type. The directed orientation is
preserved per viewpoint, so a PARENT_OF edge stays parent->child whether edited
from either person's page.
Ownership mismatch now returns 404 RELATIONSHIP_NOT_FOUND (shared loadOwned
helper) for both PUT and DELETE — anti-enumeration, replacing DELETE's former
403. No @Version: last-write-wins, matching person edit (single-writer archive).
REQ-004, REQ-005, REQ-006, REQ-007, REQ-008, REQ-009, REQ-012, REQ-013, REQ-018
Refs #837
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>