feat(01-01): install shadcn/ui components and lucide-react icons

- components.json configured (Radix preset, CSS variables, @/ aliases)
- src/lib/utils.ts: cn() helper with clsx + tailwind-merge
- 10 shadcn/ui components: button, card, badge, progress, input, label,
  select, separator, table, textarea
- lucide-react@0.511 installed for iconography
- clsx, tailwind-merge, class-variance-authority added as dependencies

src/lib/utils.ts

@@ -0,0 +1,6 @@
+import { clsx, type ClassValue } from "clsx";
+import { twMerge } from "tailwind-merge";
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs));
+}