fix(core): desktop e2e (#15062)

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## Summary by CodeRabbit

* **Bug Fixes**
* Sign-in flows now reliably propagate richer authentication results
(user data and session type), improving persistence and reducing
intermittent sign-in issues.
* Native token handling gains a fallback for environments without
encrypted storage, improving session reliability.

* **New Features**
* User-visible warning when sign-in is session-only because encrypted
storage is unavailable.

* **Chores**
  * Tooling ignore patterns updated to exclude .codex.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->