feat(env): Update environment configuration and enhance email functionality

- Renamed DATABASE_URL to POSTGRES_URL in .env.example for clarity.
- Added SMTP configuration for email sending, including host, port, user, password, and from address.
- Updated package.json to include new dependencies for email handling and UI components.
- Modified middleware to handle public and protected routes more effectively.
- Enhanced API routes for studies to support user roles and permissions.
- Updated database schema to include invitations and user roles related to studies.
- Improved user permissions handling in the permissions module.
- Added new utility functions for managing user roles and study access.

src/app/invite/accept/[token]/page.tsx

@@ -0,0 +1,23 @@
+import { Suspense } from "react";
+import { Loader2 } from "lucide-react";
+import { InvitationAcceptContent } from "./invitation-accept-content";
+
+interface InvitationAcceptPageProps {
+  params: { token: string };
+}
+
+export default async function InvitationAcceptPage({ params }: InvitationAcceptPageProps) {
+  const token = await Promise.resolve(params.token);
+  
+  return (
+    <Suspense
+      fallback={
+        <div className="flex items-center justify-center min-h-screen">
+          <Loader2 className="h-8 w-8 animate-spin" />
+        </div>
+      }
+    >
+      <InvitationAcceptContent token={token} />
+    </Suspense>
+  );
+}