Other minor redirect URL changes:
- app.urls.* is now deprecated
- redirectToSignOut now sets and preserves after_auth_return_to
- OAuth sign-in after_auth_return_to now carries callback-return context
<!-- CURSOR_SUMMARY -->
---
> [!NOTE]
> **High Risk**
> High risk because it changes OAuth authorization/token issuance,
redirect URL validation, and introduces a new cross-domain handoff
endpoint plus a DB migration linking authorization codes to refresh
tokens, which can affect login/session security and reliability.
>
> **Overview**
> Adds **hosted URL targets** for SDK `urls` resolution (new `{ type:
"hosted" }`/`{ type: "handler-component" }`/`{ type: "custom" }`
options), including env-driven hosted handler domain/template support
and fallback routing for unknown `/handler/*` paths.
>
> Implements a **cross-domain OAuth PKCE handoff**: a new
`/auth/oauth/cross-domain/authorize` endpoint issues one-time
authorization-code redirects bound to the caller’s session refresh
token; authorization codes now persist `grantedRefreshTokenId` and token
issuance reuses/validates ownership of that refresh token. Redirect
planning for `redirectTo*` (and OAuth callback handling) is refactored
into `redirect-page-urls.ts` to preserve `after_auth_return_to` and
cross-domain handoff params.
>
> Tightens redirect safety (e.g., `after_callback_redirect_url` is
validated/whitelisted), centralizes SDK env var reads via `envVars` with
lint enforcement, hardens `EventTracker` startup for partial DOM test
environments, and adds unit/E2E coverage plus a demo page for manual
cross-domain verification.
>
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
9197d4f32b. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **New Features**
* Cross-domain OAuth PKCE handoff flow (client + server) for hosted
sign-in.
* Hosted handler URL templating with local development domain suffix
support.
* Demo UI page to exercise hosted cross-domain sign-in/out and OAuth
flows.
* Authorization codes now preserve an associated refresh-token id to
support cross-domain exchanges.
* **Bug Fixes**
* Stricter redirect-URL validation and stronger refresh-token ownership
checks.
* More robust event-tracker startup guards in partial DOM environments.
* **Tests**
* New E2E and unit tests covering cross-domain authorize, callback
validation, and handoff flows.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
Updates `examples/demo` to Next.js 15 and adds Next.js 15 support to `packages/stack`.
The other packages and apps are still running on Next.js 14 to ensure compatibility.
