supabase config push fails 500 "Failed to decrypt data" on preview branches

# Bug report <!-- ⚠️ We receive a lot of bug reports which have already been solved or discussed. If you are looking for help, please try these first: - Docs: https://docs.supabase.com - Discussions: https://github.com/supabase/supabase/discussions - Discord: https://discord.supabase.com Before opening a bug report, please verify the following: --> - [x] I confirm this is a bug with Supabase, not with my own application. - [x] I confirm I have searched the [Docs](https://docs.supabase.com), GitHub [Discussions](https://github.com/supabase/supabase/discussions), and [Discord](https://discord.supabase.com). ## Describe the bug `supabase config push` fails with HTTP 500 "Failed to decrypt data" when pushing auth config to a remote project. API and DB config push fine; only the `config/auth` push fails, server-side, with a decrypt error tied to an `errorEventId`. Reproducible across separate invocations (different errorEventId each time, same failure mode). ## To Reproduce Steps to reproduce the behavior, please provide code snippets or a repository: 1. Have a project with existing remote auth config set (e.g. SMTP/SAML/third-party auth secrets). 2. Run: supabase config push --project-ref hsmjqwizhygxixcenvvz --yes --debug 3. Observe API config and DB (postgres) config push/confirm successfully. 4. See error on the `config/auth` step. ## Expected behavior `config push` should push auth config successfully, or return an error identifying which secret/field failed to decrypt instead of an opaque 500. ## Screenshots Local <img width="829" height="268" alt="Image" src="https://github.com/user-attachments/assets/600c284a-f75c-4a01-8f25-2996698fc695" /> Supabase dashboard resetting branch <img width="912" height="559" alt="Image" src="https://github.com/user-attachments/assets/46d29b71-1880-4e01-a152-c823d027278f" /> ## System information - OS: macOS 26.5 - Browser (if applies): N/A (CLI issue) - Version of supabase-js: N/A (not a client-lib issue — Supabase CLI) - Sup…