Net-new ordering coverage: roots and every unit's children sort by birthYear
ASC (undated last), then displayName, then stable id — so horizontal x never
depends on Map iteration order.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Assigns every person to one unit: a primary, or a spouse absorbed into the
primary's run (marriage-year order, #361 preserved). Wires the parent/child
hierarchy from each primary's structural-owner parent and records displaced
parent edges as cross-links (classified same-level vs cross-level for later
distinct rendering). Unknown-id guard covers PARENT_OF and SPOUSE_OF.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Structural-owner rule for couples: earlier birth year wins, missing year sorts
last, ties break on stable id. The single definition reused by the cross-link,
cycle and intra-family paths.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
