Flutter design system from DESIGN.md

Build the smallest complete design-system implementation that faithfully maps the design source and fits the host Flutter application. A design document is the source of visual intent, not a request to turn every number into a public constant or every described screen into a component.

Required decision point

Do not write or move design-system code until repository discovery is complete and this choice is known. If the user has not already answered it, ask exactly:

How should the Flutter design system be integrated?

A. Implement it directly in lib/design_system/.

B. Create an isolated local Flutter package and import it from the app.