feat(server): improve oidc compatibility (#14686)

fix #13938 
fix #14683 
fix #14532

#### PR Dependency Tree


* **PR #14686** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Flexible OIDC claim mapping for email/name, automatic OIDC discovery
retry with exponential backoff, and explicit OAuth flow modes (popup vs
redirect) propagated through the auth flow.

* **Bug Fixes**
* Stricter OIDC email validation, clearer error messages listing
attempted claim candidates, and improved callback redirect handling for
various flow scenarios.

* **Tests**
* Added unit tests covering OIDC behaviors, backoff scheduler/promise
utilities, and frontend OAuth flow parsing/redirect logic.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/components/affine/auth/oauth.tsx

@@ -73,11 +73,13 @@ export function OAuth({ redirectUrl }: { redirectUrl?: string }) {
               params.set('redirect_uri', redirectUrl);
             }
 
+            params.set('flow', 'redirect');
+
             const oauthUrl =
               serverService.server.baseUrl +
               `/oauth/login?${params.toString()}`;
 
-            urlService.openPopupWindow(oauthUrl);
+            urlService.openExternal(oauthUrl);
           };
 
       const ret = open();