implement better-auth auth with postgres and route protection

app/api/tasks/[taskId]/route.ts

@@ -1,4 +1,5 @@
 import { jsonError } from '@/lib/server/http';
+import { requireAuthenticatedSession } from '@/lib/server/auth-session';
 import { getTaskById } from '@/lib/server/tasks';
 
 type Context = {
@@ -6,8 +7,13 @@ type Context = {
 };
 
 export async function GET(_request: Request, context: Context) {
+  const { session, response } = await requireAuthenticatedSession();
+  if (response) {
+    return response;
+  }
+
   const { taskId } = await context.params;
-  const task = await getTaskById(taskId);
+  const task = await getTaskById(taskId, session.user.id);
 
   if (!task) {
     return jsonError('Task not found', 404);