implement better-auth auth with postgres and route protection

app/api/portfolio/refresh-prices/route.ts

@@ -1,9 +1,16 @@
 import { asErrorMessage, jsonError } from '@/lib/server/http';
+import { requireAuthenticatedSession } from '@/lib/server/auth-session';
 import { enqueueTask } from '@/lib/server/tasks';
 
 export async function POST() {
+  const { session, response } = await requireAuthenticatedSession();
+  if (response) {
+    return response;
+  }
+
   try {
     const task = await enqueueTask({
+      userId: session.user.id,
       taskType: 'refresh_prices',
       payload: {},
       priority: 80