feat(ui): add shadcn/ui base components

- Add clsx, tailwind-merge, class-variance-authority dependencies
- Add Radix UI primitives (dialog, dropdown-menu, label, select, tabs, toast, slot)
- Add lucide-react for icons
- Create components.json for shadcn/ui configuration
- Create lib/utils.ts with cn(), formatCurrency(), formatDate(), formatTime()
- Create Button component with variants (default, destructive, outline, secondary, ghost, link, accent)
- Create Input component with focus ring styling
- Create Card components (Card, CardHeader, CardTitle, CardDescription, CardContent, CardFooter)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/components.json

@@ -0,0 +1,20 @@
+{
+  "$schema": "https://ui.shadcn.com/schema.json",
+  "style": "default",
+  "rsc": true,
+  "tsx": true,
+  "tailwind": {
+    "config": "tailwind.config.ts",
+    "css": "app/globals.css",
+    "baseColor": "slate",
+    "cssVariables": false,
+    "prefix": ""
+  },
+  "aliases": {
+    "components": "@/components",
+    "utils": "@/lib/utils",
+    "ui": "@/components/ui",
+    "lib": "@/lib",
+    "hooks": "@/hooks"
+  }
+}