800bddd604
Two distinct bugs surfaced once a 3-generation tree was loaded
(Walter+Eugenie → Hans+Clara, Hans married to Hilde with child Lili):
1. Generation BFS was non-iterative. Hilde was visited as a "root"
first, assigning Lili = gen 1, then Hilde was pulled to gen 1 to
match her spouse Hans — but Lili's depth was never recomputed,
leaving her on the same row as her parents. Replaced the BFS with
an iterative longest-path assignment that re-runs (max parent gen
+ 1) and the spouse-shared-row rule together until stable.
2. No spouse adjacency. Hilde (no parents in the graph) ended up in
her own block on the far left, with Hans + Clara to her right and
the spouse line drawn straight across Clara's box. Replaced the
per-parent-set grouping with a block model:
- sibling-blocks group children of the same parent set
- loose spouses attach on the outer edge of their partner's block
- dual-loose spouse pairs merge into one 2-person block
- each block is centred so its parented members' average sits
exactly under the parent midpoint, keeping all connectors at 90°
Adds a regression test for the full Walter/Eugenie/Hans/Clara/Hilde/
Lili scenario (Lili in a deeper row, Hans+Hilde adjacent, no slanted
segments) and rewrites the viewBox tests to be position-agnostic via
a rect-centroid helper that reads the per-node `<g transform>`.
Tracked the eventual move to dagre (multi-marriage / cross-cousin /
~50+ nodes) in #361.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>