docs(subscriptions): mark orphan root cause as fixed in architecture map

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/architecture-maps/Subscriptions.md

@@ -415,7 +415,7 @@ php cli.php subscriptions:validate         # Verify data integrity
 - 66 members, 53 spouses, 86-89 children, 1-11 temporary — all matching active dependents
 - Validation: ALL CLEAN
 
-**Known limitation**: `RetroactiveMembershipService` (line 714) has `$sub['person_id'] ?? $memberId` fallback that creates orphaned records. The migration cleans these up.
+**Root cause fixed (2026-07-04)**: `RetroactiveMembershipService` previously fell back to `$memberId` for unmapped dependents — now resolves by name from the dependent table, or skips the row if unresolvable. Migration still cleans up historical orphans.
 
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