### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

When an Access Group is assigned to a **Team** (via the UI, resulting in `access_group_ids` and `access_group_models` on the team object), the `/v1/models` endpoint does not include the access group's models in its response. It only returns whatever is in the team's `models` field.

When the team's `models` is set to `["no-default-models"]`, `/v1/models` returns only `["no-default-models"]` — despite the Access Group correctly granting access to 12 models. Direct API calls to those models succeed (200 OK), proving the authorization layer works.

This makes the feature unusable for client applications (Open WebUI, etc.) that rely on `/v1/models` to populate their model dropdowns — users never see the models they're allowed to use.

### Steps to reproduce

**Setup:** 1. Create an Access Group in the UI with several models (e.g. "my-group" containing `gpt-4o`, `claude-sonnet-4-6`) 2. Create a Team with `models: ["no-default-models"]` 3. Assign the Access Group to the Team via the UI (the team now has `access_group_ids` and `access_group_models` po…