Add project README with features, installation instructions, and ELK
layout explanation. Fix license identifier from GPL-3.0 to AGPL-3.0 in
composer.json and module.php to match the actual LICENSE file. Remove
sync.sh from version control and add it to .gitignore.
Interactive SVG family tree visualization using ELK (Sugiyama) for
layout and D3 for rendering. Shows ancestors, descendants, and siblings
in a single diagram with orthogonal bus-line connectors.
Features:
- Bidirectional tree traversal (ancestors + descendants + siblings)
- Generation-aligned layout with post-processing Y-snap
- Person cards with photos, names, dates, and hover bio cards
- "More ancestors" indicator for persons with hidden parents
- Pan/zoom navigation
- Docker dev environment
