Add invitation and dashboard pages with UI components

Introduced a dynamic invitation page to display event details based on a slug, including RSVP functionality (placeholder). Added a dashboard page for authenticated users, providing a welcome message and placeholder for event management. Also implemented reusable Card UI components for consistent styling.

frontend/src/app/(main)/dashboard/events/[id]/page.tsx

@@ -0,0 +1,58 @@
+// src/app/(main)/dashboard/page.tsx
+"use client";
+
+import { useAuth } from "@/context/auth-context";
+import Navbar from "@/components/layout/navbar";
+
+export default function DashboardPage() {
+  const { user, isLoading } = useAuth();
+
+  // Show loading state
+  if (isLoading) {
+    return (
+      <div className="min-h-screen flex items-center justify-center">
+        <div className="text-center">
+          <div className="h-8 w-8 mx-auto border-4 border-t-blue-500 border-blue-200 rounded-full animate-spin"></div>
+          <p className="mt-2">Loading...</p>
+        </div>
+      </div>
+    );
+  }
+
+  return (
+    <>
+      <Navbar />
+      <div className="container mx-auto px-4 py-12">
+        <div className="max-w-7xl mx-auto">
+          <h1 className="text-3xl font-bold mb-8">Dashboard</h1>
+
+          <div className="bg-white dark:bg-slate-800 rounded-lg shadow p-6">
+            <h2 className="text-xl font-semibold mb-4">
+              Welcome, {user?.first_name || "User"}!
+            </h2>
+            <p className="text-gray-600 dark:text-gray-300 mb-4">
+              You are now logged in to EventSpace.
+            </p>
+
+            <div className="mt-8">
+              <h3 className="text-lg font-medium mb-4">Your Events</h3>
+              <div className="bg-gray-100 dark:bg-slate-700 rounded p-8 text-center">
+                <p className="text-gray-500 dark:text-gray-400">
+                  No events yet
+                </p>
+                <button
+                  className="mt-4 px-4 py-2 bg-blue-600 text-white rounded hover:bg-blue-700 transition-colors"
+                  onClick={() =>
+                    alert("Create event functionality coming soon!")
+                  }
+                >
+                  Create Your First Event
+                </button>
+              </div>
+            </div>
+          </div>
+        </div>
+      </div>
+    </>
+  );
+}