feat: add user authentication UI to header component

Add login and register dialogs, user dropdown menu with profile link and logout option, and integrate with session management hook. Prevent hydration mismatches by conditionally rendering auth elements after mount. Update package-lock.json with new @esbuild dependencies for build tooling.

components/ui/label.tsx

@@ -0,0 +1,26 @@
+"use client";
+
+import * as React from "react";
+import * as LabelPrimitive from "@radix-ui/react-label";
+import { cva, type VariantProps } from "class-variance-authority";
+import { cn } from "@/lib/utils";
+
+const labelVariants = cva(
+  "text-sm font-medium leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-70"
+);
+
+const Label = React.forwardRef<
+  React.ElementRef<typeof LabelPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof LabelPrimitive.Root> &
+    VariantProps<typeof labelVariants>
+>(({ className, ...props }, ref) => (
+  <LabelPrimitive.Root
+    ref={ref}
+    className={cn(labelVariants(), className)}
+    {...props}
+  />
+));
+Label.displayName = LabelPrimitive.Root.displayName;
+
+export { Label };
+