Contexts & State Architecture

Top-level providers wire feature modules and share state across the app:

• SitePlanContext: siteplan editing state and export options.
• GeographyContext: mode, area datasets, and layer visibility.
• ZoneCreatorContext: intersections-specific flows.
• DroppedObjectsContext: selection and operations for placed objects.
• TutorialContext: onboarding flows and tips.

See src/App.jsx for provider composition.