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/ui/button.tsx

@@ -0,0 +1,61 @@
+import * as React from "react";
+import { Slot } from "@radix-ui/react-slot";
+import { cva, type VariantProps } from "class-variance-authority";
+
+import { cn } from "@/lib/utils";
+
+const buttonVariants = cva(
+  "inline-flex items-center justify-center whitespace-nowrap rounded-md text-sm font-medium ring-offset-white transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary-500 focus-visible:ring-offset-2 disabled:pointer-events-none disabled:opacity-50",
+  {
+    variants: {
+      variant: {
+        default:
+          "bg-primary text-white hover:bg-primary-700 active:bg-primary-800",
+        destructive:
+          "bg-red-500 text-white hover:bg-red-600 active:bg-red-700",
+        outline:
+          "border border-primary-200 bg-white text-primary hover:bg-primary-50 active:bg-primary-100",
+        secondary:
+          "bg-primary-100 text-primary-800 hover:bg-primary-200 active:bg-primary-300",
+        ghost:
+          "text-primary hover:bg-primary-50 active:bg-primary-100",
+        link:
+          "text-primary underline-offset-4 hover:underline",
+        accent:
+          "bg-accent text-white hover:bg-accent-600 active:bg-accent-700",
+      },
+      size: {
+        default: "h-10 px-4 py-2",
+        sm: "h-9 rounded-md px-3",
+        lg: "h-11 rounded-md px-8",
+        icon: "h-10 w-10",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+      size: "default",
+    },
+  }
+);
+
+export interface ButtonProps
+  extends React.ButtonHTMLAttributes<HTMLButtonElement>,
+    VariantProps<typeof buttonVariants> {
+  asChild?: boolean;
+}
+
+const Button = React.forwardRef<HTMLButtonElement, ButtonProps>(
+  ({ className, variant, size, asChild = false, ...props }, ref) => {
+    const Comp = asChild ? Slot : "button";
+    return (
+      <Comp
+        className={cn(buttonVariants({ variant, size, className }))}
+        ref={ref}
+        {...props}
+      />
+    );
+  }
+);
+Button.displayName = "Button";
+
+export { Button, buttonVariants };