1.4.0

Add donut-stat chart type (v1.4.0)

Half donut with one highlighted share beside a big number, rule and statement.
Highlight sweeps clockwise on scroll-in; no hover or popup. Colours set by
design system token name via color and track-color.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KRVLDemwjzQzMr1uQJEVub