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/theme-toggle.tsx

@@ -1,5 +1,6 @@
 "use client";
 
+import { useEffect, useState } from "react";
 import { Moon, Sun, Monitor } from "lucide-react";
 import { useTheme } from "next-themes";
 import { Button } from "@/components/ui/button";
@@ -14,6 +15,22 @@ import { useTranslations } from "next-intl";
 export function ThemeToggle() {
   const { setTheme, theme } = useTheme();
   const t = useTranslations("header.theme");
+  const [mounted, setMounted] = useState(false);
+
+  // Evitar hidratação mismatch
+  useEffect(() => {
+    setMounted(true);
+  }, []);
+
+  if (!mounted) {
+    // Renderizar um placeholder durante SSR para manter layout consistente
+    return (
+      <Button variant="outline" size="icon" disabled>
+        <Sun className="h-[1.2rem] w-[1.2rem]" />
+        <span className="sr-only">Toggle theme</span>
+      </Button>
+    );
+  }
 
   return (
     <DropdownMenu>