Fall back to JWT exp claim when OAuth token response has no expires_in (#506)

plugins/auth-oauth2/src/store.ts

@@ -1,5 +1,6 @@
 import { createHash } from "node:crypto";
 import type { Context } from "@yaakapp/api";
+import { jwtExpiresAt } from "./util";
 
 export async function storeToken(
   ctx: Context,
@@ -11,7 +12,10 @@ export async function storeToken(
     throw new Error(`${tokenName} not found in response ${Object.keys(response).join(", ")}`);
   }
 
-  const expiresAt = response.expires_in ? Date.now() + response.expires_in * 1000 : null;
+  // Prefer expires_in from the response, falling back to the JWT's own exp claim
+  const expiresAt = response.expires_in
+    ? Date.now() + response.expires_in * 1000
+    : jwtExpiresAt(response[tokenName]);
   const token: AccessToken = {
     response,
     expiresAt,