Shared UI package with shadcn-svelte

Context

The dashboard and the website should look like one product. shadcn-svelte copies component source into a project rather than installing a library, so two apps would otherwise hold two copies of every component and the theme.

Decision

• One workspace package, packages/ui (@spotcraft/ui), holds the shadcn-svelte components.json, the components, cn, and the theme in styles.css.
• The theme is the shadcn-svelte preset b6RdvRWulu (vega style, neutral, square corners, Space Grotesk, lucide icons).
• Both apps use Tailwind v4 and import @spotcraft/ui/styles.css; that file declares an @source for the package's components so each app's Tailwind generates their classes.
• The package is source-only; the apps compile it. Inside it, files import each other through #ui/* package imports.

Consequences

• Components are added once, with the CLI run in packages/ui.
• The CLI lists component dependencies as dev dependencies; they have to be moved to dependencies so the apps get them.