Add offline caching and refine Live Activity

contexts/AuthContext.tsx

@@ -11,16 +11,39 @@ import {
 
 type AuthClient = ReturnType<typeof createAuthClient>;
 
+async function authFetch(input: RequestInfo | URL, init?: RequestInit) {
+  try {
+    return await fetch(input, init);
+  } catch (error) {
+    if (error instanceof Error && error.name === "AbortError") {
+      throw error;
+    }
+
+    return new Response(
+      JSON.stringify({
+        message: "Could not connect to the server.",
+        code: "NETWORK_ERROR",
+      }),
+      {
+        status: 503,
+        statusText: "Service Unavailable",
+        headers: { "content-type": "application/json" },
+      },
+    );
+  }
+}
+
 function createAppAuthClient(apiUrl: string, storagePrefix: string): AuthClient {
   return createAuthClient({
     baseURL: apiUrl,
+    fetchOptions: {
+      customFetchImpl: authFetch,
+    },
     plugins: [
           expoClient({
             scheme: "beenvoice",
             storagePrefix,
             storage: SecureStore,
-            // Avoid showing a cached session when cookies have already expired.
-            disableCache: true,
           }),
       genericOAuthClient(),
     ],