feat: enhance security by implementing HttpOnly refresh tokens and in-memory access token management

- Added isomorphic-dompurify for improved XSS protection
- Refactored token storage to use in-memory management for access tokens
- Implemented server-side route handlers for OAuth token management
- Introduced security headers in next.config.js
- Removed client-side exposure of client_secret and sensitive tokens
- Updated API interceptors to handle token refresh logic
- Cleaned up cookie management for refresh tokens

lib/auth.js

@@ -2,11 +2,8 @@ import { cookies } from "next/headers";
 
 export async function getUser() {
   const cookieStore = await cookies();
-  const raw =
-    cookieStore.get("access_token") &&
-    cookieStore.get("refresh_token") &&
-    cookieStore.get("uuid") &&
-    cookieStore.get("userInfo");
-  if (!raw) return null;
-  return raw;
+  const isAuthenticated =
+    cookieStore.get("refresh_token") && cookieStore.get("userInfo");
+  if (!isAuthenticated) return null;
+  return cookieStore.get("userInfo");
 }