feat(ui): expose app theme contract and public components

packages/ui/test/ui.test.ts

@@ -79,6 +79,9 @@ test("component-system CSS includes responsive, theme-token, focus, and reduced-
   expect(css).toContain("--color-violet-600: var(--wire-color-primary)");
   expect(css).toContain("--color-blue-600: var(--wire-color-info)");
   expect(css).toContain("--color-red-600: var(--wire-color-danger)");
+  expect(css).toMatch(/:root\s*\{[^}]*--color-violet-600: var\(--wire-color-primary\)/s);
+  expect(css).toContain(".wire-bg-primary");
+  expect(css).toContain(".wire-text-muted");
 });
 
 test("page shells leave background ownership to the page", () => {