Add first diagram type renderer with 9 custom BPMN node components,
3 edge types, compound ELK layout for pool/lane hierarchy, BFS path
highlighting on node click, and group container rendering. Includes
review fixes: integrated compound layout into computeLayout pipeline,
wired BFS highlighting via onNodeClick handler, replaced hardcoded
SVG colors with CSS custom properties for dark mode, and added 4
handles to all event nodes for multi-direction layout support.
81 web tests passing (31 new), no regressions.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
0a7838aa60