Calendar and Gantt used text-sm while Board used text-xs, causing
the tab container to change size when switching views.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Adds a new Gantt chart board view with custom SVG timeline rendering,
card-to-card dependency tracking with cycle detection, and a startDate
field on cards. Includes zoom controls (day/week/month), dependency
arrows, column-grouped task list, today marker, and real-time updates.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>