fix: use expoClient getCookie() for API requests per Better Auth docs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/native/src/lib/api-client.ts

@@ -1,32 +1,29 @@
-import * as SecureStore from "expo-secure-store";
 import { router } from "expo-router";
 import { env } from "@haushaltsApp/env/native";
 import { useAuthStore } from "../stores/auth.store";
+import { authClient } from "./auth-client";
 
 const BASE_URL = env.EXPO_PUBLIC_SERVER_URL;
-// expoClient plugin stores session token under "<storagePrefix>.session_token"
-const TOKEN_KEY = "haushaltsapp.session_token";
 
 export async function apiRequest<T>(
   path: string,
   options: RequestInit = {},
 ): Promise<T> {
   const householdId = useAuthStore.getState().activeHouseholdId;
-  const token = await SecureStore.getItemAsync(TOKEN_KEY);
+  const cookies = authClient.getCookie();
 
   const response = await fetch(`${BASE_URL}${path}`, {
     ...options,
     headers: {
       "Content-Type": "application/json",
-      ...(token ? { Authorization: `Bearer ${token}` } : {}),
+      ...(cookies ? { Cookie: cookies } : {}),
       ...(householdId ? { "x-household-id": householdId } : {}),
       ...options.headers,
     },
-    credentials: "include",
+    credentials: "omit",
   });
 
   if (response.status === 401) {
-    await SecureStore.deleteItemAsync(TOKEN_KEY);
     useAuthStore.getState().clearSession();
     router.replace("/(auth)/login");
     throw new Error("Unauthorized");

apps/native/src/lib/auth-client.ts

@@ -4,23 +4,8 @@ import { expoClient } from "@better-auth/expo/client";
 import * as SecureStore from "expo-secure-store";
 import { env } from "@haushaltsApp/env/native";
 
-// expoClient plugin stores session token under "<storagePrefix>.session_token"
-const TOKEN_KEY = "haushaltsapp.session_token";
-
 export const authClient = createAuthClient({
   baseURL: env.EXPO_PUBLIC_SERVER_URL,
-  fetchOptions: {
-    onSuccess: (ctx) => {
-      const token = ctx.response.headers.get("set-auth-token");
-      if (token) {
-        SecureStore.setItemAsync(TOKEN_KEY, token);
-      }
-    },
-    auth: {
-      type: "Bearer",
-      token: async () => (await SecureStore.getItemAsync(TOKEN_KEY)) ?? "",
-    },
-  },
   plugins: [
     expoClient({
       scheme: "haushaltsApp",